*6;?A ■ ■ ■ ; 1 i ZOOLOGICA 6 6 SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY VOLUME XXVI 1941 Numbers 1-30 PUBLISHED BY THE THE ZOOLOGICAL PARK, SOCIETY NEW YORK NEW YORK ZOOLOGICAL SOCIETY General Office: 630 Fifth Avenue, New York City OFFICERS President, Fairfield Osborn First Vice-President, Alfred Ely Chairman, Executive Committee & Second Vice-President, Laurance S. Rockefeller Treasurer, Cornelius R. Agnew General Director, Zoological Park and Aquarium, Allyn R. Jennings Assistant General Director, Harry Sweeny, Jr. Zoological Park Raymond L. Ditmars, Curator of Reptiles and Insects Lee S. Crandall, Curator of Birds Claude W. Leister, Curator of Mammals and Educational Activities Leonard J. Goss, Curator of Health William Bridges, Editor and Curator of Publications Aquarium in the Zoological Park Charles M. Breder, Jr., Director Christopher W. Coates, Aquarist Ross F. Nigrelli, Pathologist G. M. Smith, Research Associate in Pathology Homer W. Smith, Research Associate in Physiology Myron Gordon, Research Associate in Genetics Department of Tropical Research William Beebe, Director John Tee-Van, General Associate Gloria Hollister, Research Associate Jocelyn Crane, Technical Associate Consultant, Jean Delacour SCIENTIFIC STAFF Editorial Committee Fairfield Osborn, Chairman Allyn R Jennings William Beebe Charles M. Breder, Jr. Harry Sweeny, Jr Jean Delacour William Bridges CONTENTS. PAGE Part 1. May 26., 1941. 1. A New Crayfish from San Luis Potosi, Mexico. (Decapoda, Astacidae). By Horton H. Hobbs, Jr. (Text-figure 1) 1 2. A New Corydoras from Brazil. By F. R. LaMonte 5 3. Notes on Plumage Changes in the Bald Eagle. By Lee S. Crandall. (Plates I-IV) 7 4. External Characters of Six Embryo Nurse Sharks, Ginglymostoma cirratum (Gmelin). By William Beebe. (Plates I & II; Text-figures 1-4) 9 5. A Papillomatous Disease of the Gallbladder Associated with Infection by Flukes, Occurring in the Marine Turtle, Chelonia mydas (Linnaeus). By G. M. Smith, C. W. Coates & R. F. Nigrelli. (Plates I-IV; Text-figure 1) . . . . 13 6. Eastern Pacific Expeditions of the New York Zoological Society. XXIII. Polychaetous Annelids from the West Coast of Mexico and Central America. By Aaron L. Treadwell. (Text-figures 1-21) 17 7. Plankton of the Bermuda Oceanographic Expeditions. X. Polychaetous An- nelids from Bermuda Plankton, with Eight Shore Species, and Four from Haiti. By Aaron L. Treadwell. (Text-figures 1-9) 25 3. Caudal Skeleton of Bermuda Shallow Water Fishes. V. Order Percomorphi: Carangidae. By Gloria Hollister. (Text-figures 1-20) 31 ). Description of an Egg of the Long-tailed Bird of Paradise. By Lee S. Crandall. (Plate I) 47 ). On the Uterine Young of Dasyatus sabinus (LeSueur) and Dasyatus hastatus (De Kay). By C. M. Breder, Jr., & Louis A. Krumholz. (Text-figures 1 & 2) . ' 49 11. Additional Social and Physiological Aspects of Respiratory Behavior in Small Tarpon. By Arthur Shlaifer 55 12. Notes on Mexican Snakes of the Genus Trim ere surus. By Hobart M. Smith. . 61 Part 2. September 8, 1941. 13. The Life History and Bionomics of the Trematode, Zygocotyle lunata (Param- phistomidae). By Charles H. Willey. (Plates I-IV) 65 14. Eastern Pacific Expeditions of the New York Zoological Society. XXIV. Fishes from the Tropical Eastern Pacific. [From Cedros Island, Lower California, South to the Galapagos Islands and Northern Peru.] Part 1. Lancelets and Hag-fishes. By William Beebe & John Tee-Van. (Text- figures 1 & 2) 89 15. Eastern Pacific Expeditions of the New York Zoological Society. XXV. Fishes from the Tropical Eastern Pacific. [From Cedros Island, Lower California, South to the Galapagos Islands and Northern Peru.] Part 2. Sharks. By William Beeb^ & John Tee-Van. (Plates I & II; Text- figures 1-34) 93 PAGE 16. Correlations Between Structural Eye Defects and Behavior in the Mexican Blind Characin. By Charles M. Breder, Jr., & Edward B. Gresser. (Plates I— IV ; Text-figures 1 & 2) 123 17. On the Species of Otus scops. By Jean Delacour. (Text-figures 1-10) 133 18. A New Genus of Kaleege Pheasants. By Marquess Hachisuka 143 Part 3. October 31, 1941. 19. Eastern Pacific Expeditions of the New York Zoological Society. XXVI. Crabs of the Genus Uca from the West Coast of Central America. By Jocelyn Crane. (Plates I-IX; Text-figures 1-8) 145 20. Eastern Pacific Expeditions of the New York Zoological Society. XXVII. A Study of Young Sailfish ( Istiophorus ). By William Beebe. (Plates I-V; Text-figures 1-9) 209 21. On the Reproduction of Opsanus beta Goode & Bean. By Charles M. Breder, Jr. (Plates I & II) 229 22. On the Reproductive Behavior of the Sponge Blenny, Paraclinus marmoratus (Steindaehner). By Charles M. Breder, Jr. (Plates I— III ; Text- figure 1 ) 233 23. The Chromatophores of Fundulus hetcroclitus in Polarized Light. By A. M. Shanes & Ross F. Nigrelli. (Plates I— III) 237 24. New Races of Alaudidae and Timaliidae from Northern Thailand. By H. G. Deignan 241 25. Respiratory Behavior in Fishes Not Especially Modified for Breathing Air Under Conditions of Depleted Oxygen. By Charles M. Breder, Jr. (Plate I) 243 26. Eastern Pacific Expeditions of the New York Zoological Society. XXVIII. Fishes from the Tropical Eastern Pacific. [From Cedros Island, Lower California, South to the Galapagos Islands and Northern Peru.] Part 3. Rays, Mantas and Chimaeras. By William Beebe & John Tee-Van. (Plates I-IV ; Text-figures 1-40) 245 27. Erotylidae of Kartabo, Bartica District, British Guiana. (Coleoptera.) By C. H. Curran. (Plate I; Text-figure 1) 281 Part 4. December 29, 1941. 28. Further Studies on the Light Sensitivity and Behavior of the Mexican Blind Characin. By C. M. Breder, Jr., & Edward B. Gresser. (Plate I; Text-figures 1 & 2) 289 29. Eastern Pacific Expeditions of the New York Zoological Society. XXIX. On the Growth and Ecology of Brachyuran Crabs of the Genus Ocypode. By Jocelyn Crane. (Plates I & II; Text-figures 1-7) 297 30. High Speed Photographs of Flying Fishes in Flight. By H. E. Edgerton & C. M. Breder, Jr. (Plates I-VIII) 311 Index to Volume XXVI 315 ZOOLOGICA SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY 0- VOLUME XXVI Part 1 Numbers 1-12 - 'h» PUBLISHED BY THE SOCIETY THE ZOOLOGICAL PARK, NEW YORK May 26, 1941 CONTENTS PAGE 1. A New Crayfish from San Luis Potosi, Mexico. (Decapoda, Asta- cidae). By Horton H. Hobbs, Jr. (Text-figure 1) 1 2. A New Corydoras from Brazil. By F. R. LaMonte 5 3. Notes on Plumage Changes in the Bald Eagle. By Lee S. Cran- dall. (Plates I-IV) 7 4. External Characters of Six Embryo Nurse Sharks, Ginglymostoma cirratum (Gmelin). By William Beebe. (Plates I & II; Text- figures 1-4) 9 5. A Papillomatous Disease of the Gallbladder Associated with In- fection by Flukes, Occurring in the Marine Turtle, Chelonia my das (Linnaeus). By G. M. Smith, C. W. Coates & R. F. Nigrelli. (Plates I-IV; Text-figure 1) 13 6. Eastern Pacific Expeditions of the New York Zoological Society. XXIII. Polychaetous Annelids from the West Coast of Mexico and Central America. By Aaron L. Treadwell. (Text-figures 1-21) 17 7. Plankton of the Bermuda Oceanographic Expeditions. X. Poly- chaetous Annelids from Bermuda Plankton, with Eight Shore Species, and Four from Haiti. By Aaron L. Treadwell. (Text-figures 1-9) 25 8. Caudal Skeleton of Bermuda Shallow Water Fishes. V. Order Percomorphi: Carangidae. By Gloria Hollister. (Text- figures 1-20) 31 9. Description of an Egg of the Long-tailed Bird of Paradise. By Lee S. Crandall. (Plate I) 47 10. On the Uterine Young of Dasyatis sabinus (Le Sueur) and Dasyatis hastatus (De Kay). By C. M. Breder, Jr., & Louis A. Krumholz. (Text-figures 1 & 2) 49 11. Additional Social and Physiological Aspects of Respiratory Behavior in Small Tarpon. By Arthur Shlaifer 55 12. Notes on Mexican Snakes of the Genus Trimeresurus. By Hobart M. Smith 61 ZOOLOGICA SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY 1. A New Crayfish from San Luis Potosi, Mexico.1 (Decapoda, Astacidae). Horton H. Hobbs, Jr. (Text-figure 1). The new crayfish here described was taken by the New York Aquarium Cave Expedition to La Cueva Chica, a limestone cave in the State of San Luis Potosi, Mexico. An interesting ac- count of this cave was published by Mr. William Bridges in the Bulletin of the New York Zo- ological Society (Vol. XLIII, No. 3) in June, 1940. In this paper Mr. Bridges mentions the occurrence of crayfish in the cave, and at my request Dr. Charles M. Breder, Jr., of the New York Aquarium, and Mr. Marshall B. Bishop, of the Peabody Museum, have kindly lent me the 34 crayfish taken from the cave, and given me permission to describe them. Upon ex- amining this series I find that while they are closely allied to one of the most common species in the United States, they are distinct. During December, 1939, an expedition from the Department of Biology of the University of Florida collected in the states of Nuevo Leon and Tamaulipas, Mexico. A fine series of an apparently new subspecies of Cambarus bland- ingii was taken one mile north of Villa Juarez, Tamaulipas, but was not described since the collection contained no first form males. After having compared specimens of bland- ingii acutus from the southern United States with the Cueva Chica and Tamaulipas bland- ingii, I find that the specimens from Tamau- lipas are intermediate between these two, and that the Cueva Chica material represents a new race of blandingii. Cambarus blandingii cuevachicae, new subspecies. Diagnosis. Cambarus blandingii cuevachicae is a member of the subgenus Ortmannicus (i. e., the first pleopod of the first form male termi- nates in four distinct parts, and hooks are present on the ischiopodites of the third and fourth pereiopods). Rostrum broad with small lateral teeth. Areola practically obliterated (hardly broad enough to bear a single row of punctations). Carapace strongly granulate ex- cept along median dorsal surface. First pleopod of first form male similar to that of C. blandingii acutus. (See Text-fig. 1, B and D). Holotypic Male (Form I). Body subovate; compressed laterally. Abdomen narrower than thorax (1.54-1.91 cm. in widest parts, respec- tively). Width of carapace greater than depth in re- gion of caudodorsal margin of cervical groove. Greatest width of carapace about midway be- tween caudodorsal margin of cervical groove and caudal margin of cephalothorax. Areola almost obliterated in middle (hardly broad enough to bear a single row of puncta- tions) ; cephalic section of carapace about 1.7 times as long as areola (length of areola 35.2% of entire length of carapace) . Upper surface of rostrum deeply excavate; margins slightly convex distad of base, taper- ing and forming minute tubercles at base of acumen. Acumen short and broad, extending to base of distal segment of peduncle of anten- nule. Upper surface punctate; lateral margins with setiferous punctations almost to tip of apex. Subrostral ridge not evident in dorsal view. Postorbital ridges terminate cephalad in small tubercles, not spiniform. Suborbital angle absent. Branchiostegal spines present as large acute tubercles. •A contribution from the Department of Biology, Uni- versity of Florida, Gainesville, Florida. 1 2 Zoologica: New York Zoological Society [XX vl: 1 Surface of carapace strongly granulate except on dorsomedian surface of cephalic region; here, with setiferous punctations; one larger acute tubercle on either side in place of lateral spine, which is flanked by two or three slightly smaller ones. Abdomen slightly shorter than carapace (3.6- 3.79 cm.). Anterior section of telson with one spine in each posterolateral corner. Epistome broader than long ; subminaret shaped ; margins not raised ; faveolus present at base; small obtuse tubercle on median cephalic border. Eyes well developed. Antennules of the usual form with a well devel- oped spine on ventral surface of basal segment. Antennae reaching to caudal margin of telson. Antennal scale broad (broadest in middle) with a moderately well developed spine on outer dis- tal margin, reaching to distal segment oi peduncle of antennule. First right pereiopod long and relatively slender. Hand entirely tuberculate. A single row of eight strong tubercles along inner margin of palm subtended dorsad by two weaker rows and a few scattered tubercles. Very weak ridge present on upper surface of immovable finger. Another weak ridge present on outer distal mar- gin of same finger. Movable finger of right chela with minute tu- bercles along distal half of inner margin (crowded on distal third) . Lateral margin convex laterad ; two distinct rows of tubercles present on lateral margin along proximal two-thirds; an upper row of 24, arising near base of finger, and a lower row of 17 tubercles originating at base of distal three-fourtlis. A few scattered tubercles pres- ent on all surfaces near base of finger. Proximal two-fifths of outer margin with five tubercles. Distal upper, lower, and mesial surfaces setose punctate. Immovable finger of right chela with minute denticles on distal two-thirds (crowded on distal third). Mesial margin concave laterad; two distinct rows of tubercles on mesial margin: the upper row with 20 tubercles along the proximal two-thirds (the fifth is decidedly larger and more conspicuous than the others) and the lower row of 13 along the proximal three- fourths (the seventh is decidedly the largest of this row). When the lingers are brought to- gether the large tubercle on the upper side of finger lies over the movable finger and the large one on the lower row extends beneath it. Carpus longer than wide, much shorter than inner margin of palm of chela; shallow irregular furrow above. Mesial and upper mesial sur- faces tuberculate ; four large spike-like tubercles on mesial distal half; upper lateral, lateral, and ventral surfaces with setiferous punctations. Merus with dorsal, ventral, distal mesial, and distal lateral surfaces tuberculate; proximo- mesial and proximolateral surfaces with a few scattered punctations. Fourteen tubercles in a row on upper margin. Lower mesial margin with a row of 19 tubercles, and lower lateral margin with a row of 15 tubercles. Hooks on ischiopodites of third and fourth pereiopods. Both hooks are slender and simple. Coxopodite of fourth pereiopod with a large knob-like protuberance on caudomesial margin. First pleopod extending almost to coxopodite of second pereiopod when the abdomen is flexed. Tip terminating in four distinct parts. The mesial process is subspiculiform and is directed distad and laterad; is exceeded by the other processes distad. The cephalic process is corne- ous and blade-like, somewhat rounded distad, and extends distad of the other processes; it partially overhangs the central projection. The caudal process, the least conspicuous of the four distinct terminals, lies along the caudo-lateral margin of the central projection and extends barely distad of the mesial process. This (the caudal) process is corneous, and its tip is acute. The central projection is the largest of the terminal elements; it is corneous, concave mesiad and somewhat twisted. This projection is made up of two parts, the centro-cephalic which arises just cephalad of the caudal proc- ess on the lateral surface, and the centro-caudal which is somewhat larger and forms the mesial face of the central projection. These two proc- esses are fused along an oblique line visible in lateral and caudo-lateral views only. On the lateral surface of the appendage a conspicuous knob bearing long setae arises at the base of the cephalic process. Male Paratype (Form II). Differs from the male holotype in the following respects: Height of carapace greater than width (1.50-1.31 cm.). Postorbital ridges terminate cephalad in small acute tubercles. Branchiostegal spines moder- ately strong. Antennae reach anterior section of telson. Chelae smaller with less well defined tubercles, double row present on lateral margin of movable finger only. First pleopod termi- nating in four distinct parts; none corneous nor as sharply defined as in the first form male. (See Text-fig. 1, F and M). Hooks on ischio- podites of third and fourth pereiopods much reduced. Female Allotype. Differs in the following points from the first form male, holotype: Width of carapace slightly less than depth. Right subrostral ridge barely evident just caudad of base of acumen. Branchiostegal spines moderately strong. Lengths of abdomen and carapace subequal. Anterior section of telson with two spines in right posterolateral corner and none in the left (broken). Epistome slightly broader and shorter than in male. Antennae reaching fifth abdominal segment. Chelae smaller and tubercle count differing — only one row of tubercles on each opposing margin. 3 1941] Hobbs: A New Cray fish from San Luis Potosi, Mexico Text-figure 1. Cambarus blandingii cuevachicae, new subspecies. Pubescence has been removed from all structures illustrated. Figures not otherwise indicated are of C. blandingii cuevachicae. A, mesial view of first pleopod of C. blandingii acutus from Louisiana; B, mesial view of first pleopod of holotype; C, right chela of holotype; D, lateral view of first pleopod of holotype; E, lateral view of first pleopod of C. blandingii acutus from Louisiana; F, mesial view of first pleopod of male, form II; G, annulus ventralis of allotype; H, antennal scale of male paratype ; I, epistome of male paratype; J, ischiopodites of third and fourth pereiopods of first form male paratype; K, lateral view of carapace of holotype; L» dorsal view of carapace of holotype; M, lateral view of first pleopod of male, form II, Zoologica: New York Zoological Society Annulus ventralis subovate, elongate along transverse axis. Fossa projects beneath median dextral wall; sinus curving sinistrad slightly sinistrad of midventral line where it turns caudad to cut the caudal margin of the annulus. A shallow longitudinal furrow is present sinis- trad of the midventral line across the face of the annulus. Sternum just cephalad of an- nulus bearing a low tubercle on either side of the midventral line. Sternum just caudad of annulus modified into a low flat semioval struc- ture. Measurements. Holotype: carapace, height 1.71, width 1.86, length 3.79 cm.; areola, width .02, length 1.38 cm.; rostrum, width at base 1.59, length 1.89 cm.; abdomen, length 3.6 cm.; right chela, length of inner margin of palm 1.42, width of palm 1.14, length of outer margin of hand 4.23, length of movable finger 2.53 cm. Female Allotype: carapace, height 1.87, width 1.85, length 3.83 cm.; areola, width .07, length 1.36 cm.; rostrum, width at base .64, length .89 cm.; abdomen, length 3.72 cm.; right chela, length of inner margin of palm .92, width of palm 1.00, length of outer margin of hand 2.86, length of movable finger 1.85 cm. Type Locality. La Cueva Chica, a limestone cave, about one mile northeast of Pujal, San Luis Potosi, Mexico. These specimens were collected above the first waterfall. “Tumbled rocks alternated with shallow, narrow puddles. The going was difficult, but in the second puddle we forgot all about that, for Bishop spotted another crayfish. This time there was no es- cape, for the pool was scarcely a yard wide and twice as long. A couple of grabs and he had the creature. [XXVI: 1 “It was not blind. Lighter in color than the normal crayfish of the outside waters, it was fully eyed and of the common local species. That was a disappointment, but it went into the pickling jar anyway.”2 The temperature of the water was 80° F. The male holotype and female allotype and a second form male paratype are deposited in the United States National Museum. Of the paratypes, a male, form I, one male, form II, and a female are in my personal collection; one male, form I, seven males, form II, ten females, four immature males, and six immature females are in the Peabody Museum, New Haven, Con- necticut. Relationships. Cambarus blandingii cueva- chicae is most closely allied to C. blandingii acutus. Specimens collected one mile north of Villa Juarez, Tamaulipas, Mexico, seem to be somewhat intermediate between these two, par- ticularly in respect to the width of the areola. Remarks. I have been unable to discover any peculiarities in this race that seem to be associated with cave life. Bridges has pointed out that these specimens were of lighter color than the “normal crayfish of the outside water.” I have seen only preserved specimens so I can- not attest this observation. On the hairy parts of the ventral surface of these crayfish were found numerous ostracods, Entocythere cambaria Marshall, and many branchiobdellid worms, Cambarincola macro- donta Ellis.3 2 Bull. N. Y. Zool. Soc. 43 (3): 84-85. May-June, 1940. 3 Dr. Clarence R. Goodnight kindly identified this bran- chiobdellid for me. 1941] LaMonte: A New Corydoras from Brazil 5 2. A New Corydoras from Brazil. F. R. LaMonte American Museum of Natural History. Through the courtesy of the New York Aquari- um, we have secured three living specimens (approximately 15 mm.-18 mm. standard length), and seven preserved specimens (13 mm.-19 mm. standard), of a Brazilian Corydoras apparently hitherto undescribed. These fishes formed part of a collection brought to New York by Mr. Auguste Rabaut, and col- lected by him toward the end of December, 1940, in a tributary of the Amazon. The collector never heard a name given the stream, but he reached it after seven days by river boat west from Manaos, and four more days’ journey north toward the Colombian border. The country was flooded swamp, with heavy vegetation. Mr. Rabaut reports that the water was extremely acid. The specimens appear to represent two color patterns of the same species, the change in pattern probably occurring with growth. Each pattern, in certain lights, shows traces of the other. Of the three living fishes, the two larger are the “striped pattern;” of the preserved speci- mens, six are the “half and half” pattern, and the 19 mm. specimen is striped. Corydoras rabauti, new species. Description of Type. Number 15644, American Museum of Natural History, collected Decem- ber, 1940, in a tributary of the Amazon River, by A. Rabaut. Differences in body proportions of the 19 mm. striped specimen are noted in parentheses. Length to base of caudal, 15 mm. A rather chunky fish, with a short, rounded snout; the bony interorbital contained twice in the snout. There is no black hastate spot at the base of caudal, and the width of the naked area on the breast between the coracoids is equal to the diameter of the eye. The suborbital does not cover the entire cheek. The coracoids do not completely surround the pectoral bases on the surface of the body. The dorsal does not reach the adipose when laid back. The depth of the suborbital is equal to the diameter of the eye; the dorsal spine equal to the length of the snout. The flesh of the abdomen is smooth, without platelets. Snout, 2.1 in the head, its profile convex, sloping gently; interorbital, 2 (1.8); eye, 3.1. Body depth in standard length, 3 (2.7); width, 3.4 (3.1); head, 2.7 (3); snout to origin of dorsal, 1.8(2). Depth of caudal peduncle in body depth, 1.4. Lateral scutes spinous, 18-20/17-20 (20/21). Lateral line pores are visible on the first two or three scutes only. The abdomen is not granular and there are no platelets. Fontanel elongate, oval, reaching two-thirds the way to the anterior margin of eye and, pos- teriorly, to the supra-occipital process. Occipital process very narrowly triangular, not reaching azygous predorsal scute. Rictal barbels just reaching the gill-opening. Dorsal I, 8; the spine 1.8 (1.5) in the head. The fin is rounded, the first few rays longer than the spine. Distance of the dorsal fin from the adipose, 1.3 in the dorsal base. Anal I, 6, reach- ing past origin of caudal. Pectoral passing origin of ventrals to about midway in their length; ventrals barely reaching anal. Caudal widely forked, tip of lower lobe slightly rounded. Color in Life. Head region to short distance in front of dorsal, pinkish-orange. A dull, dark blue streak along anterior margin of eye socket, a short, very narrowly triangular metallic blue streak along posterior margin of pre-opercle. All fins except caudal, which is hyaline, are light orange, the dorsals and ventrals darkest. An ink-blue area, very slightly lighter ventrally, occupies the posterior two-thirds of the body, extending, with a concave anterior marginal outline, from in front of the dorsal origin to in front of the ventrals, entirely around the body, and back to the caudal base. On the caudal peduncle, the dark blue area becomes a short, thin line, margined by two square patches of metallic light blue. The eye is blue. In pre- servative, the lighter fins are hyaline; the dorsal and ventrals brown; the pinkish-orange body areas are faintly pink, buff or dirty light brown according to the original intensity of color; the lighter blue areas disappear as do the metallic patches; the ink-blue areas are darker and more dense. In the 19 mm. striped pattern fish (A. M. N. H. Number 15645), the ink-blue area is confined 6 [XXVI: 2 Zoologica: New York Zoological Society chiefly to a band, curving upward from the upper half of the caudal peduncle, following the midline of the body, but above it, and rising to a short distance in front of the dorsal origin. There are traces of bluish below this stripe on the entire posterior half of the body. The rest of the body is pinkish-orange, darkest on the head. The metallic light blue patches are as in the other fish. There is a trace of bluish on the middle rays of the caudal, not extending to the margin. In preservative, the body of this fish is creamy, slightly darker on the head, and the ink-blue areas are darker than in life. The species is very near eques (Steindachner, 1877, Sitz. K. Akad. Wien, volume 74, Abt. 1, p. 140. fig.), from which it differs in: a wider interorbital; a wider naked area on breast; a narrower suborbital which does not cover the entire cheek; a larger eye; longer barbels, and an apparently different color pattern. 1941] Crandall: Notes on Plumage Changes in the Bald Eagle 7 3. Notes on Plumage Changes in the Bald Eagle. Lee S. Crandall Curator of Birds, New York Zoological Park. (Plates I-IV). In August of 1930 a young Southern Bald Eagle ( Haliseetus leucocephalus leucocephalus (Linnaeus)), just out of the nest and barely able to fly, was captured on Little St. Simon’s Island, Georgia, by Philip Berolzheimer, of New York. In December of the same year, the young bird was brought north by Albert C. Benninger, of Brooklyn. It was kept in Forest Park, Queens, New York City, until June, 1931, when it was lent to the Girl Scout camp at Iona Island, Rock- land County, New York. On September 2, 1931, the bird was presented to the New York Zoo- logical Park and became the subject of the fol- lowing notes. In past years, we had made several attempts to check the progressive plumages of young Bald Eagles but always some catastrophe over- took the bird before the investigation had gone very far. Consequently, on the arrival of this specimen, no notes were made. However, in the autumn of 1933, we were able to plan indoor winter accommodation for the Bald Eagles and were so confident that greater longevity could be obtained that notes on our young individual were made. On October 10, 1933, the bird being three years old and in its fourth year, the body plumage was blackish-brown in general, the breast and lower parts much mixed with white. Forehead and throat were streaked with white, and the tail (Fig. 1) was heavily blotched with gray but with no pure white. The iris was dark brown and the beak greenish-black. On January 29, 1934, it was noted that the white streaks on the forehead had spread over the entire crown. The throat had become nearly clear white and a band of white extended to the nape. Between this band and the mottled area of the crown, was a parallel dark band, extending from the lores to the nape and passing through the eyes. During the following summer, this pattern was entirely lost. On September 2, 1934, the head, neck and throat were grayish-white, clearest on the throat but elsewhere blotched with blackish-brown, more heavily on the hind neck. The tail (Fig. 2) was extensively blotched with gray but still without clear white. The iris was light brown and the beak had become light olive, with a hint of yellow. The voice, too, was changing, for while the bird still began his call with the harsh notes of immaturity, he ended with the clear challenge of the adult. It was during the autumn of 1935, when the bird was five years old and in its sixth year, that it assumed what might be considered its first adult plumage. On November 1 of that year, the head and neck were recorded as pure white. The tail (Fig. 3), also, was now predominately white, although still heavily blotched with blackish-brown. The iris had acquired the pale yellowish-white of the adult and the bill, too, had become clear, pale yellow. The harsh notes had disappeared from the voice, which was now entirely clear. The tail grown during the summer of 1936 (Fig. 4) was more clearly white but still showed a considerable flecking of blackish-brown, par- ticularly on the shafts. On November 1, 1936, it was noted that while upper and lower tail coverts were mainly white, both were heavily stippled with brown. In November of 1937, the upper and lower tail coverts were recorded as entirely white. The tail of this year (Fig 5) showed a considerable reduction in the extent of dark stippling, though this was still present. In 1938 (Fig. 6), 1939 (Fig. 7) and 1940 (Fig. 8), the markings on the rectrices became progressively reduced. But it was not until 1940, when the bird was ten years old and in its eleventh year, that all stippling disappeared from the vanes. Even then, as may be seen in the photograph of the tail in situ (Fig. 8), faint dark markings were still present on the shafts of some feathers. It seems probable that there may be a con- siderable individual variation in the extent of dark markings on the shafts of the rectrices. A Bald Eagle received at the Zoological Park on March 1, 1927, had the head and tail “white.” Examination of this bird’s tail, after its death on June 17, 1940, when it must have been at least eighteen years old, showed heavy streaking of the shafts. [XXVI: 3 S Zoologica: New York Zoological Society Examination of the dates on which feathers were cast seems to indicate no definite procedure, except that in the last four years the outer pair dropped first and simultaneously or almost so. The earliest date for the casting of the first rectrice was April 19 (1934); the latest, June 21 (1934 and 1936). The earliest date for the casting of the last rectrice was July 30 (1934); the latest, September 25 (1938). Dates assigned to the mounted feathers indicate the time at which they were cast; in each case, they were grown in the previous year. Fig. 8 shows the tail of the living bird on December 12, 1940. The tail was grown in 1940. Summary. A Southern Bald Eagle ( Haliseetus leuco- ccphalus leucocephalus (Linnaeus)), hatched in 1930, was kept in the New York Zoological Park. In the autumn of 1935, when the bird was five years old and in its sixth year, the head and neck became pure white and the tail nearly so. It was not until 1940, when the bird was ten years old and in its eleventh year, that blackish stippling disappeared from the vanes of the rectrices. Acknowledgement. The dating and mounting of the feathers shown in the accompanying photographs were done by Herbert D. Atkin, who was a Keeper in the Department of Birds of the New York Zoological Park from 1905 to 1940, when he retired on pension. His painstaking cooperation made possible their presentation here. EXPLANATION OF THE PLATES. Plate I. Fig. 1. Haliceetus l. leucocephalus. 1933 tail feathers (bird 3 years old; in 4th year) molted in 1934. Fig. 2. 1934 tail feathers (bird 4 years old; in 5th year) molted in 1935. Plate II. Fig. 3. 1935 tail feathers (bird 5 years old; in 6th year) molted in 1936. Fig. 4. 1936 tail feathers (bird 6 years old; in 7th year) molted in 1937. Plate III. Fig. 5. 1937 tail feathers (bird 7 years old; in 8th year) molted in 1938. Fig. 6. 1938 tail feathers (bird 8 years old; in 9th year) molted in 1939. Plate IV. Fig. 7. 1939 tail feathers (bird 9 years old; in 10th year) molted in 1940. Fig. 8. Tail feathers of the living bird (10 years old; in 11th year) photographed in situ on December 12, 1940. CRANDALL PLATE I FIG. 1. FIG. 2. NOTES ON PLUMAGE CHANGES IN THE BALD EAGLE CRANDALL. PLATE I I. FIG. 3. FIG. 4. NOTES ON PLUMAGE CHANGES IN THE BALD EAGLE. CRANDALL. PLATE I I I FIG. 5. NOTES ON PLUMAGE CHANGES IN THE BALD EAGLE. CRANDALL PLATE IV. 1 ) Dald AGLE. AIL EATHERS Dec. /Z,/?AO. FIG. 8. NOTES ON PLUMAGE CHANGES IN THE BALD EAGLE. 1941] Beebe: External Characters af Six Embryo Nurse Sharks 9 4. External Characters of Six Embryo Nurse Sharks, Ginglymostoma cirratum (Gmelin).1 William Beebe (Plates I & 11; Text-figures 1-4). Six embryo nurse sharks, Ginglymostoma cirratum (Gmelin), taken from a single female, have been kindly loaned to me for the study of external characters, by Commodore William K. Vanderbilt. They are borrowed from his marine museum at Huntington, Long Island, and were obtained from Mr. Louis L. Mowbray. The parent was said to be about five feet in length, and was caught in Bermuda. It was not possible to stain or section the specimens, as I agreed to return the embryos in their present condition. The material consists of six embryos which I have designated as A to F. They are nicely graduated as to size and degree of development, and in total length measure from 73 to 152 mm. They are free, in the sense of being without shells or egg-cases, but each is attached by a short, twisted, umbilical-like extent of tissue with a large, rounded or oval mass of yolk. In his recent monograph on Chlamydoselachus (Bashford Dean Memorial Volume Archaic Fishes, Article VII, American Museum, N. Y.), Dr. E. W. Gudger writes, “The tropical, shallow- water nurse shark, Ginglymostoma cirratum carries in each greatly dilated uterus as many as 21 huge, thick-shelled eggs.” As regards the subsequent history of these uterine eggs, Gudger on strong circumstantial evidence believes that this shark is ovoviviparous, and that when the young are pretty well developed, they break out of their shells, and these latter are cast out while the embryos are retained in the uteri during further development. A photograph of one of the unbroken egg-cases, 140 mm. long, is shown on page 560 of the Memorial Volume. The total lengths of the six embryos under consideration are as follows: Embryo A, 73 mm.; B, 104; C, 107; D, 125; E, 138, and F, 152 mm. The relationship by weight of embryo to yolk is from 5.7% to 33%. In embryo A the fin-folds are still sufficiently in evidence to confuse any fin base measure- ments. The first dorsal is joined to the second 1 Contribution No. 612, Department of Tropical Re- search, New York Zoological Society. Contribution from Bermuda Biological Station for Re- search, Inc. dorsal, and this to the caudal, by the continuation of the fin in a groove beneath the surface profile of the body. The same is true of the anal which extends forward in a subdermal groove to the vertical of the pel vies. The translucent dorsal fins in this smallest embryo show thirteen in- cipient rays in the first, and ten in the second. External gills are present in all but embryo F, the largest. There is a gradual absorption in length of these filaments in the first five speci- Embryo A, length 73 mm. Side view with yolk sac (X%). Dorsal view of head showing external gill filaments from spiracle and gill-slits. (X6). 10 Zoologica: New York Zoological Society [XXVI: 4 mens. This is evident in the relationship per- centage between gill filaments and total lengths, 20%, 9.6%, 8%, 4.5%, and 3%. The smallest embryo shows the interesting condition of four external gill filaments projecting from the right spiracle, the longest of which measures 1.7 mm. in length. None are visible in the left spiracle. In the same smallest nurse shark embryo the anterior or first gill-slit shows twenty-six long filaments and a cluster of short ones at the top of the slit. A progressively larger number spring from the next three slits, while the fifth, which is directly below the fourth, has only four filaments, these, however, being of greater length than any of the rest. This general relationship holds good for the larger embryos. The climax of numerical development of ex- ternal gill filaments occurs in D, the 125 mm. individual. The next larger, with a total length of 138 mm., has lost all the filaments from the left first and second slits, although they are present on the right side. In E, of 138 mm., this asymmetry is reversed, the right anterior slits being free. The filaments are absorbed from be- low upward, the last to disappear being close to the dorsal ends of the slits. Those from the fourth and fifth slits are the final ones to vanish. F, of 152 mm. length, shows no external evi- dences of filaments. In the two youngest em- bryos the fifth slit is directly beneath the fourth, but from here on to the adult shark, it is slightly behind the fourth. As to color and pattern, the 73 mm. embryo is unspotted, as are full-grown sharks. Spots first appear, although weak and sparse, in the 104 mm. individual, and increase in strength and number up at least to embryos of 152 mm. length. In 300 mm., free-swimming nurse sharks the spots are small or obscured by the general dark pigmen- tation. A 385 mm. specimen taken on the Zaca expedition, is immaculate. Detailed examination shows that the pattern of spots can be quite asymmetrical (specimen C, with seven spots on the right side of the body, and fifteen on the left side); or symmetrical (specimens C, E and F, with numerous transverse bands on the head and body), or somewhat irregular (specimen G). Coppery color is ap- parent in the irides of the 152 mm. individual. The smallest and largest of seven specimens (including the six embryos, and a 385 mm. free- swimming young shark), are females. Claspers are evident in all the rest. In the 104 mm. embryo they are 4.5 mm. long, wholly attached 1941] Beebe: External Characters of Six Embryo Nurse Sharks 11 to the inner edge of the pelvic fins, and extending to within 1 mm. of the posterior rim of these fins. There is a gradual increase in size until in the 385 mm. shark the claspers are 13 mm. long, 9 mm. below the posterior fin border, and free for 6 mm. of their length. As the cirri or tentacles develop, their tips curve around and down, into the corners of the mouth, inside the lateral flap. This condition also holds in the young, free-swimming sharks, the tentacles being thus partly hidden and pro- tected when not in use. In the course of embryonic development of Ginglymostoma from an embryo of 73 mm. to a full-grown shark of 2,090 mm. total length, we find there are six characters showing a percentage of increase relative to the total length, and seven- teen which are on the minus side. The body depth is somewhat greater in the adult, the general flattening being especially noticeable in unborn individuals. The head, both in length and width, snout, preoral, interorbital and in- ternarial, all show relative reduction in the adult, as much as 3.7% in head length, and 4.4% in the snout. The mouth width, on the contrary, is slightly greater. The eye, length of tentacle and of spiracle are markedly less in the full grown shark. The heights of the three median fins, first and second dorsals and anal enlarge steadily from early em- bryo onwards, even reaching a 4.6% increase. The pectorals exceed these, registering width and length increases of 5.7% and 7.6%. There is considerable reduction in antero- posterior measurements from snout to first and second dorsals, as well as to pectorals, pelvics and anal fins. The bases of all the median fins are relatively less in the adult, partly because of the slow disappearance of the fin-fold. 12 Zoologica: New York Zoological Society [XXVI: 4 Text-figure 4. Embryo F, length 152 mm. Right and left side views with yolk sac. We may safely deduce that throughout the life of this shark there is an increasing need for large pectorals and a general flattening of the body in relation to the bottom-living habits, while correlated with this is a reduction of the head, with its tentacles, eyes and spiracles, and a relative shortening of the whole body. In fact, Ginglymostoma tends in development rather to- ward a bottom-living, ray-like type, than to a mid-water, shark-like organism. Developmental characters showing a plus per- centage in relation to total length are these : depth 2%, pectoral length 7.6%, pectoral width 5.7%, first dorsal height 4.6%, second dorsal height 2.3%, anal height 1.3% and mouth width 1%. Characters showing minus percentage in develop- ment are head 3.7%, head width 1.7%, snout 4.4%, interorbital 4.6%, eye 2%, snout to first dorsal 4.6%, snout to second dorsal 3%, snout to pectoral 4.6%, snout to pelvics 5.2%, snout to anal 3.6%, first dorsal base 2.1%, second dorsal base 2.3%, anal base 3.1%, snout to mouth 2.6%, tentacle length 2.5%, internarial 1.3% and spiracle length .5%. EXPLANATION OF THE PLATES. Plate I. Fig. 1. Embryo B, length 101 mm. Shark, showing external gill filaments and yolk sac. Fig. 2. Embryo D, length 125 mm. Shark, showing right side and yolk sac. Plate II. Fig. 3. Embryo F, length 152 mm. Dorsal and right side views and yolk sac. Fig. 4. Embryo F, length 152 mm. Ventral view and yolk sac. BEEBE PLATE I FIG 1. FIG 2 EXTERNAL CHARACTERS OF SIX EMBRYO NURSE SHARKS, GINGLYMOSTOMA CIRRATUM (GMELIN). BEEBE PLATE I I. FIG. 3. FIG. 4 EXTERNAL CHARACTERS OF SIX EMBRYO NURSE SHARKS. GINGLYMOSTOMA CIRRATUM (GMELIN). 1941] Smith: A Papillomatous Disease of the Gallbladder 13 5. A Papillomatous Disease of the Gallbladder Associated with Infection by Flukes, Occurring in the Marine Turtle, Chelonia my das (Linnaeus).1 G. M. Smith Department of Anatomy, Yale School of Medicine, and the New York Aquarium & C. W. Coates & R. F. Nigrelli New York Aquarium (Plates I— IV ; Text-figure 1). In two earlier publications attention was called to certain cutaneous tumors occurring in the turtle Chelonia mydas (Linnaeus) (Smith & Coates, 1938, 1939). These growths, fibro- epithelial in character, are found distributed on the neck and in the axillary, inguinal, eyelid, conjunctival and corneal regions. As a rule the tumors have the morphological characteristics of benign growths ; rarely does the structure suggest a malignant change. In the majority of such tumors ova of a blood fluke can be demonstrated on microscopical study, giving rise to the hy- pothesis that blood flukes or ova may act as causative factors in the production of these lesions. In earlier studies ova occurring in cu- taneous tumors were identified as those coming from Hapalotrema constrictum (Leared). Recent studies of a number of these worms (Nigrelli, 1940), however, indicate that this blood fluke is the same as Distomum constrictum of Leared (1862) and the form described by Price (1934) as Learedius learedius. The form described as Ha- palotrema constrictum (Leared) Looss, 1899 ( = Mesogonimus constrictum Monticelli, 1896) is now designated as Hapalotrema mistroides (Monticelli). This form is also a blood fluke but found in an- other species of marine turtle Caretta caretta (Lin- naeus) (= Thalassochelys caretta (Linnaeus)). It must lie pointed out here, however, that the original identification was tentative and based on the shape and size of the eggs, which are strikingly similar. Relationships and identifications of worms have been based on egg characteristics by various taxonomists. Further studies of lesions in turtles as a result of fluke infections, carried on during the past year, have revealed a new form of papillomatous disease of the gallbladder of Chelonia mydas 1 Aided by a grant from the Marine Cancer Fund of Yale University School of Medicine. which may be the result of a fluke infection of this organ. A brief description of the gallbladder lesions and of the fluke itself follows. Infected gallbladders show a wide range of lesions, depending doubtless upon the intensity and duration of the infection and the suscepti- bility of the tissues of the host. Any part of the fundus of the gallbladder may show thickened papillomatous change in solitary patches (Plate I, Fig. 1; Plate II, Fig. 4) or in confluent irregular masses (Plate I, Fig. 2). A papillomatous hyper- plasia of the mucous membrane near the cystic duct’s entrance into the gallbladder may be the most conspicuous lesion, the result of infection by trematodes (Plate II, Figs. 4, 5,6). Inconsequence, the cystic end of the gallbladder may appear greatly thickened and encroaching on the lumen of the gallbladder (Plate IV, Fig. 12) almost to the point of producing a stenosis or obstruction. At times the entire wall of the gallbladder partici- pates in the lesion. In these circumstances the epithelium is thrown up into papillomatous folds (Plate III, Figs. 7, 8), the muscularis shows in- creased amounts of connective tissue and lymph- oid cell infiltration and the subserosa may be oedematous, thickened, and contain a large number of dilated capillaries both vascular and lymphatic. All sorts of irregularly dilated glands are formed in the hyperplastic epithelium. Often glands penetrate down into the submucosa. However, malignant invasive changes have not been noted to date in approximately one hundred gallbladders examined which have shown the effects of fluke infection. Malignant change might readily be expected as a result of these chronic hyperplastic changes. In order to de- termine whether or not the papillomatous lesions do become malignant it will be necessary to have 14 [XXVI: 5 Zoological New York Zoological Society access to more extensive material than is avail- able at the present time. The majority of the flukes lie free in the dark green, thickened, often inspissated bile of the infected gallbladder. Flukes often are attached to the papillomatous parts of the mucous mem- brane (Plate IV, Fig. 11). The parasites may lie partly buried in the mucosa (Plate I, Figs. 1, 2). There can be little doubt that the presence of flukes at the site of characteristic lesions of the mucous membrane indicates that the underlying- cause of the disease arises in mechanical or chemical factors related to the activities of the infecting flukes. Ova surrounded by epithelioid or even giant cells may be found in the mucous membrane or other parts of the walls of the gall- bladder (Plate III, Fig. 9). Mucous production is abundant (Plate III, Fig. 10). The parasites from the gallbladder of Chelonia mydas have been identified as Rhytidodoides similis Price, 1939. A related species R. intesti- nalis was described in the same paper. According to Price, the identifications of “Both R. intesti- nalis and R. similis are in each case based on only two specimens; consequently it is not possible to determine the amount of variation within the species.” A collection of large numbers of the gallbladder form has afforded an opportunity to make just such a study for this species, at least (Text-figure 1). The worms are lanceolate in shape, tapering at both ends of the body and broadening consider- ably in the middle region. The posterior tip of the body can be extended into a minute “tail- like” appendage. When the flukes are examined in profile there is a characteristic hump on the dorsal side. In contracted specimens, the hump is more pronounced than in the extended forms. On the ventral surface, the acetabulum is promi- nent'and immediately anterior to this sucker may be seen the genital ridge and pore. The flukes are transparent and stained with bile. They measure 1.2 x .42-4.4 x 1.8 mm., with an average size of 2.2 X .97 mm. for fifty specimens. Cuticula without spines, smooth in expanded worms, with minute folds in contracted specimens. Oral sucker subterminal, measuring 140.2-342 microns in diameter (average, 293.4 microns), with lateral projections. The projec- tions are prominent in the smaller individuals, less so in larger forms but are nevertheless a constant feature. Acetabulum, 170.3-385.6 microns (average, 300.7 microns), pre-equatorial. Pre-pharynx lacking; pharynx 80-179 X 50-170 microns; esophagus of variable length, depending entirely on the state of contraction and expansion of the worms. Intestinal ceca simple, extending to the posterior extremity of the body. Excretory pore subterminal, dorsal; excretory vesicle Y- shaped, branching immediately behind the pos- terior testis, with the arms extending as far anterior as the pharynx. Genital aperture median, anterior to the ventral sucker and in the region of the cecal bifurcation. Cirrus pouch elongate piriform, muscular, situated over or slightly in front of the acetabulum, measuring 150-700 microns X 150-456 microns (average measurement 152 X 478.8 microns). Seminal vesicle and pars prostatica present. Testes in posterior third of the body, placed one behind the other or slightly oblique to the axis of the body, sometimes globular, sometimes sub-globular or ovoid in shape. Anterior testis usually smaller, measuring 102-420 microns X 250-456 microns; posterior testis 152-532 microns in diameter. In very small forms testes and vitellaria are poorly developed. Ovary globular, 91-280 microns in diameter (average, 250 microns), sub-median and pre-testicular in position. Ovarian complex, con- sisting of Mehlis’ gland, seminal receptacle, vital- line reservoir, and Laurer’s canal. Vitellaria consist of four groups of more or less elongated follicles; two small groups of follicles are in the anterior region of the body and present as two distinct masses, one on each side of the esophagus between the acetabulum and pharynx; the two larger groups extend from the acetabulum to the posterior extremity of the body. Main vitelline ducts pass medially into the ovarian complex at about the level of the posterior border of the ovary. Uterus fills the entire intercecal space between the ovary and acetabulum; metraterm present. Eggs yellowish, thick-shelled, embryo- nated, measuring on the average 36 X 72 microns. Comment. The histo-pathology of trematode infections among lower vertebrates is not well known. The condition reported above is in many respects not unlike liver fluke infections in mammals (see Craig & Faust, 1940). In sheep liver fluke, Fasciola hepatica Linnaeus, larvae are ingested with contaminated vegeta- tion. Excystment takes place in the duodenum where the parasites penetrate the wall and pass into the body cavity. They continue their migration, passing through the liver capsule directly into the liver substance. The mechanical irritation produced, in the case of heavier infec- tions, results in necrosis and fibrosis of the liver. Such an infection in man may cause cystic en- largement of the ducts, adenomata of the biliary epithelium, leucocytic and eosinophilic infiltra- tion, and eventually the development of scar tissue. Often, in their wanderings through the liver substance, the worms produce abscesses, and the mechanical damage causes atrophy of the liver and the portal vessels. Local lesions of this kind may be produced by other liver flukes such as the lancet fluke, Dicrocoelium dentriticum (Rudolphi), the cat liver fluke, Opisthorchis felineus (Rivolta), and the Chinese liver fluke, Clonorchis sinensis (Cobbold). In dicrocoeliiasis, sheep and other herbiverous mammals become infected by eating grass and other vegetation containing encysted larvae. When eaten, such larval forms excyst in the duodenum and find their way to the biliary passages, often producing hypertrophy of the 1941] Smith: A Papillomatous Disease of the Gallbladder 15 epithelium. Both opisthorchiasis and clonor- chiasis infections are brought about by eating fish poorly cooked, improperly cured, or raw, harboring the encysted stage. In clonorchiasis, the larvae, following excyst- ment, make their way up the common bile duct and migrate to the distal bile capillaries. Lesions produced by such infections have been described by Faust & Khaw (1927), Hoeppli (1933) and others. These include the proliferation of bili- ary epithelium, crypt formation in the bile duct, periepithelial fibrosis, periportal connective tissue hyperplasia and fibrous development around masses of eggs infiltrated in the liver substance. Although the papillomatous disease of the gallbladder of Chelonia mydas is stressed in the present contribution, there are also definite re- sponses in the liver and biliary ducts of these 16 [XXVI: 5 Zoologica: New York Zoological Society animals which will be discussed in a subsequent report. Summary. 1. Gallbladders of the marine turtle Chelonia mydas (Linnaeus) were found heavily infected with a fluke referred to as Rhytidodoides similis Price, 1939. 2. These flukes produce certain pathological changes in the tissues of the gallbladder. The outstanding feature of these lesions is a papillo- matous hyperplasia of the mucous membrane. 3. The parasites inducing these lesions are redescribed. References Cited. Craig, C. F. & Faust, E. C. 1940. Clinical Parasitology. Lea and Febiger, Phila. 772 pp., 244 text-figures. Faust, E. C. & Khaw, O. H. 1927. Studies on Clonorchis sinensis (Cobbold). Amer. Jour. Monogr. Series, (8), 339 pp. Hoeppli, R. 1933. Histological changes in the liver of sixty- six Chinese infected with Clonorchis sinen- sis. Chinese Medical Journal, JR': 1125- 1141. Leared, Arthur 1862. Description of a new parasite found in the heart of the edible turtle. Quart. J . Micr. Soc., London, n. s., 2: 168-170. Looss, A. 1899. Weitere Beitrage zur Kenntnis der Trema- toden-Fauna Aegyptens zugleich Versuch einer naturlichen Gliederung des Genus Distomum Retzius. Zool. Jahrb., Jena, Abt. f. Syst., 12: 521-784. Monticelli, F. S. 1896. Di un ematozoo della Thalassochelys caretta Linn. Internat. Monatschr. f. Anat. u. Physiol., Leipz. 13: 141-172. Nigrelli, R. F. 1940. Observations on Trematodes of the Marine Turtle, Chelonia mydas. Anat. Rec., 78, no. 4, Supph: 178. Price, Emmett W. 1934. New Genera and species of blood flukes from a marine turtle, with a key to the genera of the family Spirorchidae. J. Washington Acad. Sci., 24: 132-141. 1939. A new Genus and two new species of digenetic trematodes from a marine tur- tle. Proc. Helminth. Soc., Washington, 6: 24-25. Smith, G. M. & Coates, C. W. 1938. Fibro-epithelial growths of the skin in large marine turtles, Chelonia mydas (Linnaeus). Zoologica, 23: 93-98. 1939. The occurrence of trematode ova, Hapalo- trema consirictum (Leared), in fibro- epithelial tumors of the marine turtle, Chelonia mydas (Linnaeus). Zoologica, 24: 379-382. EXPLANATION OF THE PLATES. Plate I. Fig. 1. Strip of gallbladder mucous membrane showing to the right a small papilloma with several flukes attached to or partly buried in the mass. Fig. 2. Photograph of inside of gallbladder attached to the liver. Note confluent masses of papillomatous tissue; flukes lie attached or partly buried in the growth. Plate II. Fig. 3. Section of normal gallbladder containing bile. Fig. 4. Thickened, shrunken, infected gallbladder with several small papillomata near the entrance of the cystic duct. Figs. 5-6. Small contracted gallbladders infected by fluke, Rhytidodoides similis. The great thickening of the mucosa and submucosa has occurred near the cystic duct. Plate III. Figs. 7-8. Irregular hyperplasia of papillomatous regions of infected gallbladders. X 35. Fig. 9. Photo-micrograph of papillomatous region of gallbladder showing fragments of ova at points a and b. Epithelioid cells surround the small fragment at b. X 120. Fig. 10. Masses of mucous formed at the surface of papilloma. X 100. Plate IV. Fig. 11. Microscopic section of trematode Rhytido- doides attached to the hyperplastic epi- thelium of the gallbladder. Section of the parasite is at the level of the ventral sucker and the cirrus sac. X 40. Fig. 12. Photo-micrograph of the cystic end of infected gallbladder. The hyperplastic mucous membrane is thrown into countless folds which encroach upon the lumen of the gallbladder. Submucosa and muscularis are thickened. The subserosa seen in the upper part of the photograph is oedema- tous and contains numerous blood and lymphatic vessels. X 25. SMITH PLATE I. (Ill INI III! II 1! HI i mi in 1 IITI Nil mi mi i 2 3 4 1 i m ) o 7 FIG. 2. A PAPILLOMATOUS DISEASE OF THE GALLBLADDER ASSOCIATED WITH INFECTION BY FLUKES, OCCURRING IN THE MARINE TURTLE, CHELONIA MYDAS ( LINNAEUS ) . SMITH. PLAT FIG. 3. FIG. 4. FIG. 5. A PAPILLOMATOUS DISEASE OF THE GALLBLADDER ASSOCIATED WITH INFECTION BY FLUKES. OCCURRING IN THE MARINE TURTLE CHELONIA MYDAS ( LINNAEUS ) . SMITH PLATE III FIG. 7 FIG. 8. FIG. 9. FIG. 1 O . A PAPILLOMATOUS DISEASE OF THE GALLBLADDER ASSOCIATED WITH INFECTION BY FLUKES. OCCURRING IN THE MARINE TURTLE. CHELONIA MYDAS (LINNAEUSl SMITH PLATE IV. FIG. 1 1 . FIG 12. A PAPILLOMATOUS DISEASE OF THE GALLBLADDER ASSOCIATED WITH INFECTION BY FLUKES. OCCURRING IN THE MARINE TURTLE CHELONIA MYDAS ( LINNAEUS) . 1941] Treadwell: Polychaetous Annelids from Mexico 17 6. Eastern Pacific Expeditions of the New York Zoological Society. XXIII. Polychaetous Annelids from the West Coast of Mexico and Central America.1 Aaron L. Treadwell Department of Zoology, Vassar College (Text -figures 1-21). Contents. Introduction .17 Systematic Account. Family Amphinomidae Hermodice carunculata Kinberg 17 Notopygos ornata Grube 18 Chloeia euglochis Ehlers 18 Eurythoe, complanata Pallas 18 Eurythoe oculata sp. nov .18 Family Polynoidae Lepidasthenia picta Treadwell . 18 Lepidasthenia elegans sp. nov 19 Halosydna brevisetosa Kinberg 20 Family Sigalionidae Eupholoe nuda Treadwell 20 Polyodontes californicus sp. nov 20 Family Aphroditidae Aphrodita Linnaeus 21 Family Phyllodocidae Phyllodoce oculata Ehlers 21 Phyllodoce groenlandica Oersted . . . ..21 Eulalia magnapupula sp. nov. '. .21 Family Tomopteridae Tomoptcris opaca Treadwell . . 22 Family Typhloscolecidae Travisiopsis atlantica Treadwell 22 [This is the twenty-third of a series of papers dealing with the collections of the Eastern Pacific Expeditions of the New York Zoological Society made under the direction of Dr. William Beebe. The present paper is concerned with specimens taken on the Eastern Pacific Zaca (1937-1938) Expedition, which was made possible through the generosity of Mr. Templeton Crocker. For data on localities, dates, dredges, etc., refer to Zoologica, Vol. XXIII, No. 14, pp. 287-298.] Introduction. The following is a taxonomic account of 30 species of polychaetous annelids collected by Dr. William Beebe on the Eastern Pacific Zaca Ex- pedition in 1937-1938. Five new species are 1 Contribution No. 613, Department of Tropical Re- search, New York Zoological Society. Family Leodicidae Leodice longisetis Webster .22 Leodice paloloides Moore .22 Diopalra ornata Moore 22 Hyalinoecia juvenalis Moore .22 Arabella pacifica sp. nov 23 Family Amphictenidae Peclinaria gouldii Verrill 23 Family Opheliidae Ammotrypane bermudiensis Treadwell 23 Family Capitellidae Notomastus sp 23 Family Glyceridae Hemipodus mcxicanus Chamberlin 23 Family Chlorhaemidae Stylarioides sp 23 Family Terebellidae Terebella gorgonae Munro 23 Terebellides stroemi Sars 23 Family Sabellidae Sabella melanostigma Schmarda 23 Bibliography 24 included in the collection. They were collected from off Cedros Island, Lower California, on the north to Panama Bay on the south. The catalogue numbers all refer to specimens in the collections of the Department of Tropical Research of the New York Zoological Society. Systematic Account. Family Amphinomidae. Hermodice Kinberg. Hermodice carunculata Kinberg. Hermodice carunculata Kinberg, 1857, p. 13. Collected at Arriba Isthmus, Port Parker, Costa Rica, January 17, 1938, Cat. No. 3,882A. 18 Zoologica: New York Zoological Society [XXVI: 6 Notopygos Grube. Notopygos ornata Grube. Notopygos ornata Grube, 1856, p. 55. Collected at Station 203: D-9 (Port Parker, Costa Rica, January 22, 1938, 2 fathoms), Cat. No. 381,093. Chloeia Savigny. Chloeia euglochis Ehlers. Chloeia euglochis Ehlers, 1887, pp. 18-24; pi. 1, figs. 1, 2; pi. 2, figs. 1-8; pi. 3, figs 1M. Collected at Station 195: D-9 (Port Guatulco, Mexico, December 5, 1937, in 7 fathoms), Cat. No. 37,477. Collected at Port Guatulco, Mexico, December 5, 1937, in fish trap at 7 fathoms. Color plate Z-118, Cat. No. 37,429. Station 221 : D-l (Gulf of Chiriqui, Panama, March 13, 1938, 35 fathoms), Cat. No. 38,659. Specimen 37,477. Dorsal surface iridescent purplish-gray with a wide blackish band down the middle of each side within which are numer- ous oblique yellow streaks. On the mid-dorsal line of each segment are a pair of longitudinal, slightly oblique yellow lines. Tentacles and dor- sal cirri greenish-black; setae bright orange. Gills greenish-brown, with a central yellow band on each stem. Eurythoe Kinberg. Eurythoe complanata Pallas. Eurythoe complanata Pallas, Teste McIntosh. McIntosh, 1885 (as E. pacifica Kinberg), pp. 27, 28; pi. 2, figs. 3, 4; pi. 3, fig. 3; pi. 2A, fig. 13; pi. 3A, figs 5-9. Collected at Station 195: D-15 and D-16 (Port Guatulco, Mexico, December 6, 1937, in 1J4 fathoms), Cat. No. 37,526. Sihuatanejo, Mexico, November 24, 1937, in coral, Cat. No. 37,266. Station 196: D-18 (Tangola-Tangola Bay, Mexico, December 13, 1937, 30 fathoms), Cat. No. 37,743. Aba,jo Rocks, Port Parker, Costa Rica, January 22, 1938, tide-pool, Cat. No. 381,094. Eurythoe oculata sp. nov. (Text-figures 1-3). A single specimen. The body is broken and more or less macerated near its middle so that accurate measurements are impossible but it is approximately 180 mm. long. The greatest width, 10 mm., is at about the end of the anterior third of the body length. The prostomial width is 1 mm. The prostomium (Text-fig. 1), is ovate with its broader end anterior, and has two pairs of promi- nent eyes. The anterior tentacles are slender and reach as far as to the anterior prostomial border. The median tentacle is relatively long, is attached at the level of the posterior eyes and extends to the anterior border of the anterior ones. The tentacles are colorless, as is the prostomium. The caruncle is very small and inconspicuous and is attached to the dorsal border of the first somite (Text-fig. 1). This prostomium has certain re- semblances to that of E. duhia Horst as redefined by Munro (1933, p. 5), but is longer in proportion to width than in his figure 1, the eyes are much more prominent and the tentacles more slender. Horst (1912, p. 37), and Munro describe the caruncle as fiexuous though this is more clearly shown in Horst’s figure than in Munro’s. In oculata it is hardly more than a rounded papilla. The parapodial lobes are widely separated. The dorsal cirrus is prominent and lies anterior to the tuft of gills. Two dorsal aciculae with rounded ends protrude to the surface at the base of the cirrus and three similar aciculae occur in the neuropodium (Text-fig. 2). The ventral cir- rus is a rounded cone. The notosetae make up a dense tuft, are all alike, long, slender and sharp- pointed. Sometimes it is possible to see on the shafts the denticles figured by Horst ( loc . cit., pi. 10, fig. 7), but generally they seem smooth. I am uncertain what he meant by “dimples” on the shafts, and can find nothing that would answer to this description. The neurosetae (Text-fig. 3), are heavy, with apices bluntly rounded and an also bluntly rounded, subapical tooth. The gills first appear on the third somite and when well developed consist of a tuft of 12 or more filaments arising from a common base just behind the insertion of the dorsal cirrus. A few filaments may be simple but most are at least 2-branched and some are irregularly dichoto- mously divided into as many as 6 branches. The type was collected at the dock in Balboa, Panama, July 25, 1933. It is a female with eggs, and is No. 3,319 in the collection of the Depart- ment of Tropical Research of the New York Zoological Society. Family Polynoidae. Lepidasthenia Malmgren. Lepidasthenia picta Treadwell. Lepidasthenia picta Treadwell, 1928, pp. 456, 457; fig. 177; figs. 10-13. A single specimen in this collection makes possible additions and corrections to the original diagnosis. The drawing (loc. cit., fig. 10), shows a dividing line between the lateral prolongation of the prostomium and the cirrophore of the tentacle. This is incorrect. The cirrophore is a prolongation of the prostomium. In the type the palps and elytra were missing. In the Zaca material the former show as stout structures shorter than the median tentacle and having acuminate tips. The anterior elytra are approxi- mately circular in outline and cover the tentacles which may be seen through them. The anterior dorsal margin of the elytron is faintly tinged with black and there is a small black spot ventral to the point of elytrophore attachment. Later elytra are more lateral in position, leaving a con- 1941] Treadwell: Polychaeious Annelids from Mexico 19 Text-figures 1-21. 1-3. Eurythoe oculata sp. nov. 1, head X 7; 2, parapodiuin X 0; 3, neuroseta X 62. 4-7 . Lepidas- thenia elegans sp. nov. 4, head X 12; 5, parapodium X 20; 6, notoseta X 180; 7, neuroseta X 180. 8, Elytron of Eupholoe nuda Treadwell X 25. 9-12. Polyodontes calif ornicus sp. nov. 9, head X 18; 10, parapodium X 5; 11, seta X 85; 12, seta X 180. 13-17. Eulalia magnapupula sp. nov. 13, dorsal surface of headX 10; 14, ventral surface of head X 10; 15, parapodium X 33; 16, seta X 250; 17, seta X 250. 18-21. Arabella pacijica sp. nov. 18, head X 15; 19, seta X 68; 20, maxilla X 23; 21, mandible X 23. siderable portion of the dorsum exposed. While anterior elytra are lightly pigmented, throughout the median and posterior regions the pigmenta- tion is dense except for a colorless spot over the elytrophore, this giving an ocellated appearance to the dorsal surface. The elytra have neither marginal fringes nor surface spines. The body coloration is somewhat different from that of the type, indicating some degree of variability. Collected at Station 203: D-9 (Port Parker, Costa Rica, January 22, 1938, in 1^2 to 4 fath- oms), Cat. No. 381,092. Lepidasthenia elegans sp. nov. (Text-figures 4-7). Two specimens are in the collection, the type being incomplete. This is 25 mm. long and 10 mm. wide at the tenth somite. In the other, which is entire, the posterior region is badly pre- served and it is impossible to determine the number of somites or of the elytra. The speci- mens are assigned to this genus subject to later correction. The prostomium (Text-fig. 4), is 1 mm. in diameter, is broader than long and has a 20 Zoological New York Zoological Society [XXVI: 6 broad but not deep, anterior indentation into which fits the heavy cirrophore of the median tentacle. From the base of this indentation a dorsal groove runs posteriorly along the pros- tomial surface. The eyes are all near the pos- terior border, the posterior ones the smaller, nearer together and more or less covered by the margin of the first somite. The median cirro- phore is heavy, its length rather more than half that of the prostomium. The style is about as long as the prostomium up to the point where it begins to taper and it has a slender terminal filament. Cirrophores of the lateral tentacles are short and stout, their styles shaped much like those of the median but only about two-thirds as long. The ventral tentacular cirrus is similar in form to the median tentacle, the dorsal one similar to the lateral tentacle but much more slender. The palps are slender and inconspicu- ous, hardly longer than the median tentacle. The first somite, carrying the elytrophore, is twice as wide as the prostomium, later ones in- crease in width up to the sixth. The coloration is unlike in the two specimens, the type having five or six dark transverse bands on its dorsum in each somite, while the other has two irregular ones in this locality. Except for a slight tint near the apex of the palp there is no color in the head region. The parapodium has a much reduced notopo- dium into which a stout acicula extends, the neuropodium is much heavier and rounded at the apex, anterior and posterior lobes equal (Text- fig. 5). The dorsal cirrus is on a heavy cirrophore whose diameter is more than half that of the parapodium, its style reaching considerably be- yond the parapodium apex, slightly swollen near the end and terminating in a heavy filament. The ventral cirrus is very short, conical and has a slender tip. All but one of the notopodia examined had no setae, the exception having a single one. This was rather heavy, its apex bluntly rounded (Text-fig. 6), and it has trans- verse rows of teeth along one border, these being heavier than those in the neuropodium. There are about ten setae in the neuropodial group, these differing from one another mainly in size. They have rather heavy stalks which are swollen near the ends and then narrow to blunt points. Very small teeth, difficult to see unless the seta is in the proper position, occur along one margin of the swollen portion (Text-fig. 7). The protruded pharynx is as long as the first seven somites. Dorsally and ventrally at its apex are marginal rows of nine papillae. Anteriorly the elytra cover the dorsum. I am unable to say what the condition is in later somites. All elytra are circular in outline, the surface dotted with pigment spots and devoid of marginal filaments. The specimens are recorded as commensal in a holothurian. They were collected at Station 126: D-14 (East of Cedros Island, Mexico in 45 fathoms), Cat. No. 3,773. The type is in the collection of the Department of Tropical Re- search of the New York Zoological Society. Halosydna Kinberg. Halosydna brevisetosa Kinberg. Halosydna brevisetosa Kinberg, 1865, p. 85. Collected at Station 126: D-19 (S. E. of Cedros Island, Mexico, November 10, 1937, in 25 fath- oms), Cat. No. 3,794. Family Sigalionidae. Eupholoe McIntosh. Eupholoe nuda Treadwell. (Text-figure 8). Eupholoe nuda Treadwell, 1936, pp. 53, 54; figs. 10-14. As Eupholoe nuda I described a specimen from Bermuda in which I was uncertain whether all elytra had been lost or whether they had ever been present. The present collection contains one of this species with a full complement of elytra. They are decidedly lateral in position, leaving a considerable portion of the dorsum un- covered, and are essentially of the same form throughout the body. They, as well as the body surface, are covered with sand grains of which the largest on the elytra are those of the antero- dorsal area, some of which protrude beyond the elytral border (Text-fig. 8). The smallest of the grains are at the posterodorsal region where there are also some long marginal filaments. On the posteroventral face are two branched filaments and small ones occur on the remainder of the border except for a small part of the dorsal region where there are neither filaments nor sand grains. At this region the elytral surface is dotted with small spines. My earlier material showed two kinds of com- pound setae ( loc . cit., figs. 13, 14), one much heavier than the other, the slender one with a subterminal tooth. The present material shows that the subterminal tooth is present on both kinds of setae but evidently is easily broken away. The setae differ, therefore, only in size. Collected at Station 126: D-19 (S. E. of Cedros Island, Mexico, November 10, 1937, in 25 fathoms), Cat. No. 3,794. i Polyodontes californicus sp. nov. (Text-figures 9-12). The type and only specimen is a fragment, measuring 25 mm. to the region of the 20th ely- tron, and has a width of 10 mm. The prostomial diameter is about 1 mm., each half continued into an ommatophore, the base of each ommatophore being at about half way of the total prostomial- eye length, the apex of the eye being a trifle wider than the width of the stalk. There is a lens at the end. The sessile eyes are a pair of small dark spots, one on either side (Text-fig. 9). The base of the median tentacle is at the level of these sessile eyes and its stalk very slender, its apex narrowing to a filamentous tip which does not quite reach the apex of the ommatophore. At base of median tentacle is a ring of brownish pig- 1941] 21 Treadwell: Polychaetous Annelids from Mexico ment and a median caruncle-like ridge runs pos- teriorly across the dorsal prostomial surface. The lateral tentacles are similar to the median in form and size but are not visible from the dorsal sur- face, being hidden beneath the ommatophores. Each has a pigmented ring at the base and anoth- er just proximal to the filamentous tip. The palps are slender, nearly three times as long as prosto- mium and ommatophores combined and are pig- mented near the apices. The basal portion of the tentacular cirri extends as far as the base of the ommatophores, the styles slender, extending as far as the apex of the eyes, their apices abruptly ending in slender filaments. There is a band of brown pigment near the apex of the cirrophore and the dorsalmost cirrus has pigment near its apex and another pigmented mass near its base. The protruded pharynx extends 10 mm. be- yond the prostomium and at its apex is 7 mm. wide. The dorsalmost terminal papilla of the pharynx is 4 mm. long and on either side of it a row of 7 broad, flattened papillae with acute apices. The outermost one of each row is much the smallest and in most of them is a dark spot. The ventral median papilla is short, similar to, but a little larger than, the lateral ones of which there are 6 on either side. There are two light brown fangs with a single row of teeth on either side of each pair. The protrusion of the pharynx produces enough distortion so that it is not possible to determine exactly the position of the anterior elytra. Evi- dently the first pair covers the prostomium and is colorless except for a few widely distributed black spots. The second is much smaller than the first, the third larger than the second but still smaller than the first. These have a few dark spots. The fourth is about as large as the third and diffusely pigmented. Beginning with the fifth, a considerable area of the dorsal surface is uncovered by elytra and these assume a very characteristic coloration and form. Each is ap- proximately oval in outline, its long axis vertical and the outer end wider than the inner. Near the dorsal end is a densely pigmented band, separated by a colorless band from the elytron margin. From one-half to one-third of the ely- tron surface shows more or less pigmentation, the densest portion being the dorsal area mentioned above. The combined effect is that of two dark brown bands along the dorso-Iateral surface of the body. A very faint brownish tint, due to numerous small transverse lines, marks the dorsal surface beneath the elytra. The remainder of the body is colorless. The first pair of ventral cirri are very large, following ones successively smaller, most reaching only to end of parapodium. The dorsal cirri are nearly of the same size throughout. A median parapodium has nearly equal an- terior and posterior setal lobes and a spoon- shaped lip underlying the neuropod (Text-fig. 10). The dorsal cirrus has a heavy cirrophore and a conical style reaching a short distance beyond the setal lobe. The ventral cirrus is much more slender, its acute tip just about reaching the end of the neuropod. There are three types of setae. The first lie in the median portion of the row, have heavy brown shafts slightly enlarged and curved toward ends, apex obliquely truncated (Text-fig. 11). To this truncated portion is at- tached a slender terminal joint having fine hairs on its surface. Above and below these are slender setae, their apices very slender lanceolate in outline, the terminal portion covered by fine hairs. Another and larger tuft of colorless setae lies ventral to the heavy ones. These (Text-fig. 12) widen toward the ends and are curved. At the curve are toothed plates and beyond these, fine hairs cover the entire surface. The gills are bladder-like structures on the dorsal parapodial surfaces and are most promi- nent on the elytra-bearing somites. This species is here classed in the genus Polyodontes, because of the presence of gills. If, however, Chamberlin’s synonymy is correct (1919, p. 86), Polyodontes is preoccupied and it should be listed as Acoetes. The type was collected at Station 182: D-4 (Chamela Bay, Mexico, November 17, 1937, in 16 fathoms), Cat. No. 37,152, and is in the col- lection of the Department of Tropical Research of the New York Zoological Society. Family Aphroditidae. Aphrodita Linnaeus. Specimens of Aphrodita, all too badly pre- served to admit of species identification, were collected at Station 189: D-2 (17 miles S. E. by E. of Acapulco, Mexico, November 29, 1937, in 20 fathoms), Cat. No. 37,742; Station 195: D-17 (Port Guatulco, Mexico, December 7, 1937, in 6 fathoms), Cat. No. 37,741; Station 214: D-3 and 4 (14 miles S. by E. of Judas Point, Costa Rica, March 1, 1938, in 50 and 61 fathoms), Cat. No. 38,409. Family Piiyllodocidae. Phyllodoce Savigny. Phyllodoce oculata Ehlers. Phyllodoce oculata Ehlers, 1887, pp. 135-140; pi. 40, figs. 4-6. Collected at Station 220: L-2 (Isla Parida, Gulf of Chiriqui, Panama, March 12, 1938, surface light), Cat. No. 38,650; Station 126: D-19 (S. E. of Cedros Island, Mexico, November 10, 1937, in 25 fathoms), Cat. No. 3,794. Phyllodoce groenlandica Oersted. Phyllodoce groenlandica Oersted, 1842-43. Teste McIntosh. McIntosh, 1908-10, pp. 86-88; pi. 58, fig. 5; pi. 68, figs. 4-6; pi. 78, fig. 7. Collected at Station 223: L-l (Bahia Hermosa, Coiba Island, Panama, March 19, 1938, at sur- face light), Cat. No. 38,760. Eulalia magnapupula sp. nov. (Text-ligures 13-17). Characterized by very large eyes and short 22 Zoologica: New York Zoological Society [XXVI: (3 tentacles and cirri. Two specimens, of which the type is the larger but is incomplete. The smaller is 57 mm. long and in the anterior body region is 4 mm. in diameter to the ends of the setae. The posterior end is very narrow and possibly regenerating. In the preserved material the anterior margin of the prostomium is rounded, the lateral margins straight and running directly into the eyes (Text-fig. 13). The paired tentacles are heavy cones hardly longer than wide, only the anterior ones visible from the dorsal surface. The median tentacle is inconspicuous and is situated at about the middle of the dorsal prostomial surface. The eyes are very large, either one being larger than the exposed portion of the prostomium. Their lenses are visible only from the sides. The ten- tacular cirri are one pair on the first somite, two pairs on the second and one pair on the third (Text-fig. 14). The cirrophores of dorsal one on second and third pairs are heavy and about as long as the styles. The style of the third pair is the longest but this barely reaches the third somite. The eyes are dark brown, the peristomial surface is marked by brown pigment, cirrophores of tentacular cirri dark brown, styles colorless. Anteriorly the body color is light brown with a tendency toward a transverse dark band near the anterior margin of the somite and a darker spot on the anterior margin of the parapodium. This latter spot becomes more prominent posteriorly, and posterior to about the twenty-fifth somite is carried on a definite rounded lobe. The flattened dorsal cirri are more or less spotted with brown. Anteriorly on the ventral surface the pigmenta- tion is diffuse, while posteriorly there is a dark spot at the base of each parapodium. On the midventral portion of each somite is an uncol- ored spot shaped like a thickened H which is prominent against the diffuse brown of the general surface. Neither specimen retains the anal cirri. The parapodium is conical (Text-fig. 15), the posterior lip the longer and terminating in a fila- mentous tip, the acicula protruding from the surface by the side of this filament. Between the two lips arises a fan-shaped seta tuft. The dorsal cirrus is broad-lanceolate on a heavy cirrophore and reaches about as far as the end of the fila- ment on the setal lobe. The ventral cirrus is shorter than the setal lobe, heavy, with recurved tip. There are two kinds of setae, the first simple, bluntly rounded and slightly curved at the tip (Text-fig. 16), the other compound, with a long basal joint, the terminal joint slender and sharp-pointed (Text-fig. 17). In the type the pharynx is protruded to a dis- tance equal (in preserved material), to the length of the first eight somites. The type was collected at Station 225: T-l (11 miles S. W. by S. of Jicaron Island, Panama, March 20, 1938, in 500 fathoms), Cat. No. 38,767. Another specimen was taken at Station 227 : T-l (20 miles S. W. of Morro de Puercos, Panama, March 21, 1938, in 500 fathoms), Cat. No. 38,789. The type is No. 38,767 in the collection of the Department of Tropical Research of the New York Zoological Society. Family Tomopteridae. Tomopteris Eschscholtz. Tomopteris opaca Treadwell. Tomopteris opaca Treadwell, 1928, pp. 463, 464, fig. 178: fig. 29. Collected at Station 210: T-10 (20 miles south of Cape Blanco, Costa Rica, February 27, 1938, in 500 fathoms), Cat. No. 38,391. Station 233: T-l (55 miles south of Cape Corrientes, Colombia, April 3, 1938, in 500 fathoms), Cat. No. 38,908. Family Typhoscolecidae. Travisiopsis Levinsen. Travisiopsis atlantica Treadwell. Travisiopsis atlantica Treadwell, 1936, pp. 62, 63; figs. 30-33. Collected at Station 227 : T-l (20 miles S. W. of Morro de Puercos, Panama, March 21, 1938, in 500 fathoms), Cat. No. 38,789. Family Leodicidae. Leodice Savigny. Leodice longisetis Webster. Leodice ( Eunice ) longisetis Webster, 1884, pp. 317, 318; pi. 10, figs. 46-49. Collected at Sihuatenejo, Mexico, November 24, 1937, in coral, Cat. No. 37,266. Leodice paloloides Moore. Leodice paloloides Moore, (?) 1919, pp. 246-249; pi. 7, figs. 5-7. Collected at Sihuatanejo, Mexico, November 24, 1937, in coral, Cat. No. 37,266A. Diopatra Aud. et M. Ed. Diopatra ornata Moore. Diopatra ornata Moore, 1911, pp. 273-277; pi. 18, figs. 77-85. Collected at Station 196: D-1S (Tangola- Tangola Bay, Mexico, December 13, 1937, in 30 fathoms), Cat. No. 37,645A. Hyalinoecia Malmgren. Hyalinoecia juvenalis Moore. Hyalinoecia juvenalis Moore, 1911, pp. 277- 280; pi. 18, figs. 86-95. Collected at Station 203: D-2 (Port Parker, Costa Rica, January 20, 1938, in 10 fathoms), Cat. No. 38,109A. 1941] Treadwell: Polychaetous Annelids from Mexico 23 Arabella Grube. Arabella pacifica sp. nov. (Text-figures 18-21). The body is broken about at its middle but the entire animal is preserved, the total length being 160 mm. The body width is 3 mm., the pro- stomial width 1.3 mm. The prostomium is rounded (Text-fig. 18) and no eyes are visible. The anterior parapodia are very small, later ones increase in size but the posterior ones are small. There are two anal cirri, these being short with rounded ends. On the parapodia are prominent dorsal lobes extending to the ends of the setae. Setae are of only one kind (Text-fig. 19), having slender stalks widened and geniculate toward the extremities with very sharp apices and a pair of toothed wings at the bend. In profile only one of the wings is visible and unless slightly tilted the marginal denticulations do not appear. In each parapodium are three aciculae protruding only very slightly from the surface. All mouth parts jet black. In the maxilla the terminal plate on either side has only one tooth (Text-fig. 20). No. 2 has on either side a 6- toothed plate; No. 3 on either side 7 teeth. The forceps are heavy and overlie the proximal plates so that without destroying the specimen it was not possible to determine the precise number of teeth in each of the latter, but they extend as far as the forceps base and are toothed for the greater part of their length. Apparently also the inner margin of the forceps is toothed. The basal rods are very long, less than half of them being shown in the figure The mandible is rectangular with a forked base (Text-fig. 21). The type was collected at Sihuatanejo, Mexico, November 24, 1937, in coral, Cat. No. 37,266, and is in the collection of the Department of Tropical Research of the New York Zoological Society. Family Amphictenidae. Pectinaria Lamarck. Pectinaria gouldii Verrill. Pectinaria gouldii Verrill, 1873, p. 612; figs 87, 87A. Collected off Ballenas Bay, Gulf of Nicoya, Costa Rica, February 26, 1938, in mangrove mud, Cat. No. 38,359A. Family Opheliidae. Ammotrypane Rathke. Ammotrypane bermudiertsis Treadwell. Ammotrypane bermudiensis Treadwell, 1936, pp. 60, 61; figs. 24-26. Collected at Station 208: D-3 (Piedra Blanca Bay, Costa Rica, February 5, 1938, in 4 fathoms), Cat. No. 38,187A. Family Capitellidae. Notomastus Sars. A single specimen of undetermined species was collected at Station 126: D-16 (East of Cedros Island, Mexico, November 10, 1937, 42 fathoms), Cat. No. 3,781. Family Glyceridae. Hemipodus Quatrefages. Hemipodus mexicanus Chamberlin. Hemipodus mexicanus Chamberlin, 1919, pp. 349-350; pi. 63, figs. 2-3. Collected at Station 126: D-16 (East of Cedros Island, Mexico, November 10, 1937, in 42 fathoms), Cat. No. 3,781A. Family Chlorhaemidae. Stylarioides Della Chiaje. Stylarioides sp.? Collected at Station 221 : D-5 (Gulf of Chiriqui, Panama, March 13, 1938, in 35-40 fathoms), Cat. No. 38,659A. Family Terebellidae. Terebella Linnaeus. Terebella gorgonae Munro. Terebella gorgonae Munro, 1933 A, pp. 1070, 1071, fig. 18. Collected at Station 203: D-9 (Port Parker, Costa Rica, January 22, 1938, in 2 fathoms), Cat. No. 38,111. Terebellides Sars. Terebellides stroemi Sars. Terebellides stroemiSavs, 1835. Teste McIntosh. McIntosh, 1922, pp. 209-215; pi. 120, fig. 3; pi. 127, fig. 5. Collected at Station 126: D-16 (East of Cedros Island, Mexico, November 10, 1937, in 42 fath* oms), Cat. No. 3,781A. A single specimen of an empty tube of a tere- bellid, strongly resembling that of Lanice figured by McIntosh (1885, pi. 49, fig. 4), was collected at Station 224: D-3 (Hannibal Bank, Panama, March 20, 1938, in 35 fathoms), Cat. No. 38,755. Family Sabellidae. Sabella Linnaeus. Sabella melanostigma Schmarda. Sabella melanostigma Schmarda, 1861, p. 36. Elders, 1887, p. 263. Collected at Sihuatanejo, Mexico, March 24, 1937, in coral, Cat. No. 37,266A. 24 Zoologica: New York Zoological Society [XXVI : G Bibliography. Chamberlin, R. V. 1919. The Annelida Polychaeta. Memoir Mu- seum of Comparative Zoology, Harvard College, vol. 48, pp. 1-514; pis. i-80. Ehlers, Ernst 1864-68. Die Borstenwurmer, pp. 1-722; pis. 1- 24. 1887. Florida Anneliden. Memoir Museum of Comparative Zoology, Harvard College, vol. 15, pp. 1-335; pis. 1-60. Fauvel, Pierre 1916. Resultats des Compagnes Scientifiques ac- complies sur son yacht par Albert ler, Prince Souverain de Monaco. Monaco, Fasc. 48, pp. 1-152; pis. 1-9. Grube, A. E. 1856. Annulata Oerstediana. Vitensk. Meddel. fra d. Naturh. Foren. Kjobenh, pp. 44-62. Horst, R. 1912. Polychaeta errantia. Siboga Exp. Mono- graphs, vol. 24A, 43 pp.; 10 pis., Pt. 1, Amphinomidae. Kinberg, J. G. H. 1857. Ofversigt K. Vetensk. Akad. Fork., pp. 11- 14. 1865. Ofversigt K. Vetensk. Akad. Forh., pp. 167-180. McIntosh, W. C. 1885. Challenger Expedition Reports, vol. 12, pp. i-xxxvi; 1-554; pis. 1-55; 1A-39A. 1908-10. Monograph of the British Annelids. Ray Society Publication, vol. 2, Nephthy- didae to Ariciidae; pp. 1-524; pis. 43-87. Moore, J. Percy 1 909. Polychaetous annelids from Monterey Bay and San Diego, California. Proc. Acad. Nat. Science, Philadelphia, vol. 61, pp. 235-295; pis. 7-9. 1911. Polychaetous annelids dredged by the U. S. S. Albatross off the coast of Southern California in 1904. III. Euphrosynidae- Goniadidae. Proc. Acad. Nat. Science, Philadelphia, vol. 63, pp. 234-318; pis. 15-21. Munro, C. C. A. 1933. Polychaeta errantia collected by Dr. C. Crossland at Colon, in the Panama region and the Galapagos Is. Proc. Zool. Soc. London, pt. 1, pp. 1-96; text-figs. 1-36. 1933A. Polychaeta sedentaria collected by Dr. C. Crossland at Colon in the Panama region and the Galapagos Is. Proc. Zool. Soc. London, pt. 4, pp. 1039-1092; text-figs. 1-31. Schmarda, Ludwig 1861. Neue wirbellose Thiere. Bd. 1, Hft. 2, pp. 1-164; pis. 16-37. Treadwell, A. L. 1906. Polychaetous annelids of the Hawaiian Is. Bull. U. S. Fish Commission for 1903, pt. 2, pp. 1145-1181, 81 figs. 1928. Polychaetous Annelids from the Arcturus Oceanographic Expedition. Zoologica, vol. 8, no. 8, pp. 449-485, figs. 177-179. 1936. Polychaetous annelids from the vicinity of Nonsuch Id. Bermuda. Zoologica, vol. 21, pt. 1, pp. 49-68; 3 pis. 1937. Polychaetous Annelids from the West Coast of Lower California, the Gulf of California and Clarion Island. Zoologica, vol. 22, pt. 2, pp. 139-160, 2 pis. Verrill, A. E. 1873. Invertebrate Animals of Vineyard Sound. Report U. S. Fish Commission for 1872. Annelids, pp. 580-622; pis. 10-17. Webster, H. E. 1884. Annelida from Bermuda. Bull. U. S. National Museum, no. 25, pp. 305-327, 12 pis. 1941] Treadwell: Polychaetous Annelid* from Bermuda Plankton 7. Plankton of the Bermuda Oceanographic Expeditions. X. Polychaetous Annelids from Bermuda Plankton, with Eight Shore Species, and Four from Haiti.1 Aaron L. Treadwell Department of Zoology, Vassar College. (Text-figures 1-9). Con . 25 . 25 . 26 . 26 . 26 . 26 . 27 . 27 . 28 . 2S . 28 . 28 . 28 TENTS. Family Leodicidae Leodice stigmatura Verrill 28 Leodice culebra Treadwell 28 Leodice mutilata Webster 28 Family Syllidae Autolytus bidens sp. nov 28 Iiaplosyllis gula Treadwell 29 Family Amphictenidae Pectinaria gouldii Verrill 29 Family Opheliidae Ammotrypane bermudiensis Treadwell 29 Family Glyceridae Telake epipolasis Chamberlin 29 Family Terebellidae Eupolymnia magnified Webster 29 Family Sabellidae Dasychonopsis conspersa Elilers 29 Family Serpulidae Spirobranchus tricornis (Morch) Elders . 29 Bibliography 29 Introduction Systematic Account. Fandly Ampldnomidae Hermodice caruncuiata Kinberg . . Family Polynoidae Lepidonotus pilosus Treadwell . . . Family Sigalionidae Acanthicolcpis longicirrata sp. nov. Family Phyllodocidao Eulalia megalops Verrill My slides gracilis sp. nov Lopadorhynchus uncinatus Fauvel Family Alciopidae Vanadis fuscapunclata Treadwell . Fandly Tomopteridae Tomopteris longiselis Treadwell . . Fandly Typldoscolecidae Travisiopsis atlantica Treadwell . Fandly Nereidae Nereis bairdii Webster Nereis mirabilis Kinberg Nereis agassizi Ehlers [This is the tenth of a series of papers dealing with the plankton content of a series of nets drawn through a cylinder of water off the coast of Bermuda on the Bermuda Oceanographic Expeditions of the Department of Tropical Research under the direction of Dr. William Beebe. Full details as to this circle of water, and of the dates, depths, etc., of the nets will be found in Zoologica, Vol. XIII, Nos. 1, 2 and 3, pp. 1-45, and Zoologica, Vol. XXI, No. 3, pp. 69-73.] Introduction. The following is an account of 23 species of polychaetous annelids collected primarily at Bermuda on the Bermuda Oceanographic Ex- 1 Contribution No. 614, Department of Tropical Re- search, New York Zoological Society. Contribution from the Bermuda Biological Station for Research, Inc. peditions of the Department of Tropical Research of the New York Zoological Society, plus materi- als relating to specimens collected on the Haitian Expedition of the Department in 1927. Three new species are described, the types of which are deposited in the collections of the Department of Tropical Research. Systematic Account. Family Amphinomidae. Hermodice Kinberg. Hermodice caruncuiata Kinberg. Hermodice caruncuiata Kinberg, 1857, p. 13. Collected at Cooper’s Island, Bermuda, in mud, Sept. 11, 1931, Cat. No. 312,029. Nonsuch Island, Bermuda in shallow water, July 23, 1929, Cat. No. 29,135. [XXVI: 7 26 Zoologica: New York Zoological Society Family Polynoidae. Lepidonotus Leach. Lepidonotus pilosus Treadwell. Lepidonotus pilosus Treadwell, 1937, pp. 141- 143, pi. 1, figs. 1-7. Collected at Bizoton, Port-au-Prince Bajq Haiti, March 22, 1927. Family Sigalionidae. Acatithicolepis Norman. Acanthicolepis longicirrata sp. nov. (Text-figures 1-4). Characterized by the long tentacles and cirri and by the large eyes. As seen from above the pigmented borders of the two eyes on either side are in contact (Text-fig. 1) and appear to run together, forming a heavy pigmented border to the prostomium. The lens of the posterior eye points laterally, thus seeming to bend the pig- mented band toward the dorsal surface. The lens of the anterior eye is not visible from above. Length 15 mm., width of prostomium 1 mm., greatest body width to parapodial bases 4 mm. in region of 9th somite. At first gradually, later more rapidly, the body tapers to about 0.5 mm. at the posterior end. Only one elytron remains and the preservation is such that it is impossible to be certain of the elytrophore count in later somites but the number is apparently 18. The prostomium is somewhat broader than long, each half ending on its anterior margin in a well marked peak. The cirrophore of the median tentacle is heavy, set into a shallow depression between the two prostomial halves. The style of the median tentacle is about the length of the palps, these 3 mm. long, colorless and curved, the apices diverging. Cirrophores of the lateral tentacles small, styles slender, reaching to about the middle of the palps. Only one tentacular cirrus and one dorsal cirrus remain, these being about as long as the palps. Each cirrus has a central opaque white core, the remainder being- translucent. Apparently the elytra originally covered the dorsal surface but only one remains. This is so transparent as to be easily overlooked. On its surface are numerous, evenly distributed, low spines visible under a 40 diameter magnifica- tion. Its outline is approximately circular. In a parapodium taken from in front of the middle of the body (Text-fig. 2) the notopodium is shorter than the neuropodium and the latter when seen from above has an inflated appearance, its longitudinal diameter being greater than that of the notopodium. The notopodial acicula is shorter but slightly heavier than the neuropodial, the former being covered nearly to its apex by a symmetrical tissue outgrowth. A similar out- growth covers the neuroacicula but there is in addition a papilla lying parallel to the acicula end (Text-fig. 2). The ventral cirrus is slender and elongated, extending for nearly half its length beyond the apex of the setal lobe. The notosetae are heavier than the neurosetae and form a diverging tuft which extends almost vertically from the notopodium. They are of two kinds, one straight and sometimes very heavy, the others shorter and curved. Both have transverse rows of plates whose margins seem not to be particularly toothed. The neurosetae are more numerous and more slender. The dorsal ones in the tuft are slender, have very sharp points and alternately arranged rows of toothed plates (detail in Text-fig. 3). Ventral to these are fewer and larger ones which enlarge toward the ends and then narrow to acute apices. A row of toothed plates lies along one margin of the tapered portion (Text-fig. 4). The type was collected in Net 1,503, 600 fath- oms deep, off Bermuda, July 25, 1934. Others were taken in Net 1,316, 800 fathoms, off Ber- muda, Sept. 17, 1931, Cat. No. 312,135. It was also taken at Station 114: T-5, 500 fathoms, in the Hudson Gorge, 125 miles off New York City, July 8, 1928. The type is No. 3,465 in the col- lection of the Department of Tropical Research of the New York Zoological Society. Family* Phyllodocidae. Eulalia Savigny. Eulalia megalops Verrill. Eulalia megalops Verrill, 1900, p. 601. Collected in Castle Harbor, Bermuda, August 13, 1931, Cat. No. 311,247. Taken in a bivalve shell in coral. Mystides Theel. Mystides gracilis sp. nov. (Text-figures 5-7). A slender species represented only by an in- complete specimen. What remains is 62 mm. long and about 1.5 mm. in diameter in greatest width. The prostomium (Text-fig. 5) has the form of a cone with rounded apex, the sides nearly straight lines. The eyes are large and have prominent lenses. Behind the prostomial margin is a small tubercle. The tentacles are about one- third as long as the prostomium. There are four pairs of tentacular cirri arranged according to the generic formula. The third pair are the longest, reaching somite 7 ; the dorsal of the second pair reaches to somite 5. Except for faint transverse lines on the anterior dorsum, the body is colorless. In most of the anterior region the dorsal cirri have been lost but those that remain are very small, barely reaching to the end of the setal lobes. Posterior ones (Text-fig. 6) are much larger, are rectangular in form and carried on heavy bases. In the setal lobe there is a slightly bifid posterior lip and a rounded one coming to the surface between them. In each parapodium there are about ten setae having rather heavy basal joints, enlarged and spiny at the ends. The terminal joints are long and slender, curved, and toothed on the concave margins (Text-fig. 7). The ventral cirri are longer than the setal lobe, have ovate outlines and acute apices. 1941] Treadwell: Polychaelous Annelids from Bermuda Plankton 27 Text-figures 1-9. 1-4. Acanthicolepis longicirrata sp. nov. 1, head X 12; 2, parapodium X 23; 3, detail of stalk of neuroseta X 180; 4, neuroseta X 85. 5-7. Mysti- des gracilis sp. nov. 5, head X 15; 6, parapodium X 33; 7, seta X 250. 8, Nereis agassizi Ehlers. Parapodium X 23. 9, Autolytus bidens sp. nov. Head X 45. The type was collected in Net 1,179, off Bermuda at the surface, August 14, 1931, Cat. No. 311,288, and is in the collection of the Department of Tropical Research of the New York Zoological Society. Lopadorhynchus Grube. Lopadorhynchus uncinatus Fauvel. Lopadorhynchus uncinatus Fauvel, 1916, pp. 57-61, pi. 1, figs. 2-3; pi. 4, figs. 4-14. Collected at Bermuda in the following nets: Net 1,321, 50 fathoms, Sept. 18, 1931, Cat. No. 312,166, color, pinkish tan; Net 1,337, 600 fath- oms, Oct. 29, 1931, color orange. Family Alciopidae. Vanadis Claparede. Vanadis fuscapunctata Treadwell. Vanadis fuscapunctata Treadwell, 1906, pp. 1159-1160, figs. 29-31. Collected in Bermuda in the following: Net 10, 400 fathoms, April 9, 1929, Cat. No. 2932; Net 1,175, 600 fathoms, Aug. 14, 1931, Cat. No. 311,761, color transparent, eyes scarlet; Net 1,262, 700 fathoms, Sept. 4, 1931, Cat. No. 311,807; Net 1,264, 900 fathoms, Sept. 4, 1931, Cat. No. 311,821, color dirty tan in general, eyes coral red; Net 1,275, 1,000 fathoms, Sept. 7, 1931, Cat. No. 311,866, color white, eyes scarlet; Net 1,308, 100 fathoms, Sept. 16, 1931, Cat. No. 312,073, color olive, eyes red; Net 1,321, 50 fathoms, Sept. 18, 1931, Cat. No. 312,167, color lemon yellow, eyes coral red; Net 1,508, 100 fathoms, Aug. 14, 1934, Cat. No. 34,256. The following field-notes were made upon specimen No. 31,472 (Net 1,050, 25 fathoms, July 6, 1931), 23 mm. long: Color: Eyes coral red with gleaming, brighter centers which are at the base of a tiny projecting crystal dome. Otherwise the animal is entirely transparent except for a yellowish, reddish, brownish or blackish spot behind the base of each lateral appendage. These spots are lightest and brightest when the worm is active or when it has been exposed for some time to bright light. There is no noticeable change in their size, except possibly a slight contraction after the worm was placed in the darkness of a refrigerator. The eyes paled only slightly when the worm was kept in darkness. As the worm weakened a growing opaqueness was noticeable. Movements: Locomotion is principally by means of the short, three-leaved, shamrock-like paired appendages which, on alternate sides, are thrown abruptly forward and back so that the worm, seen from above, has a ridiculous sort of waddle. It seems to move either ahead or in reverse with equal facility and no apparent change of method. When greatly excited it shoots through the water with tremendous con- tortions, twistings and loopings of the entire body. The partitions between the segments, as trans- parent as the body wall, are pierced by holes which, more or less rhythmically, though not in unison, expand almost to full diameter of the segment and contract nearly to pinheads. The funnel-shaped proboscis is likewise contractile. This worm remained alive in the Bermuda laboratory for two days. It was kept in a qui- escent condition in the refrigerator most of the time, but was revived at intervals of a few hours in the warm air of the laboratory. About five to ten minutes were required for it to show signs of life. [XXVI: 7 Zoologica: New York Zoological Society 28 Family Tomopteeidae. Tomopteris Eschscholtz. Tomopteris longisetis Treadwell. Tomopteris longisetis Treadwell, 1936, pp. 58-59, figs. 18-21. Collected in Bermuda, Net 1,332, 600 fathoms, Oct. 28, 1931, Cat. No. 312,227, color white. Fragments and young of toinopterids were col- lected in other nets at Bermuda, but none were identifiable. Family' Typhoscolecidae. Travisiopsis Levinsen. Travisiopsis atlantica Treadwell. Travisiopsis atlantica Treadwell, 1936, pp. 62, 63, figs. 30-33. Collected in Bermuda in the following nets: Net 793, 700 fathoms, July 9, 1930, Cat. No. 30,477; Net 869, 1,000 fathoms, Sept. 10, 1930, Cat. No. 30,844, color orange yellow; Net 881, 600 fathoms, Sept. 12, 1930, Cat. No. 30,904, color orange yellow; Net 956, 1,000 fathoms, Sept. 28, 1930, Cat. No. 301,307; Net 1,258, 900 fathoms, Sept. 3, 1931, Cat. No. 311,778; Net 1,264, 900 fathoms, Sept. 4, 1931, Cat. No. 311,820, color transparent white. Family Nereidae. Nereis Cuvier. Nereis bairdii Webster. Nereis bairdii Webster, 1884, pp. 312-313, pi. 8, figs. 22-28. Collected at the surface at Bermuda as follows : Net 982, surface, May 19, 1931, Cat. No. 3,124; Net 1,179, surface, Aug. 14, 1931, Cat. No. 311,286; dip net at night-light, Aug. 27, 1937. Those from Net 982 are in the heteronereis stage. Nereis mirabilis Kinberg. Nereis mirabilis Kinberg 1865, p. 170. Collected in Bermuda as follows: Net 982, surface, May 19, 1931, Cat. No. 3,124A; Net 1,332, 600 fathoms, Oct. 28, 1931, Cat. No. 312,286. Nereis agassizi Ehlers. (Text-figure 8). Nereis agassizi Ehlers, 1868, pp. 542-546, pi. 23, fig. 1. ‘ A single specimen, doubtfully identified as this species. Its most characteristic features are the dark parapodial glands and the single heavy spine in each parapodium lying almost in contact with the notopodial acicula on its dorsal surface (Text-fig. 8) . This also conforms with reasonable accuracy to the brief description of N. kobiensis as given by McIntosh (1885, pp. 210-212, pi. 34, figs. 3-6; pi. 16a, figs. 2-4). I was unable to get a good view of the jaw apparatus which would have been confirmatory. Both of these species have some resemblances to N. dumerilii Aud. et M. Ed., but no diagnoses that I have seen of the latter species mention the heavy spine. Collected in Bermuda, Net 1,237, 700 fathoms, Aug. 29, 1931, Cat. No. 311,651, color orange- yellow. Family Leodicidae. Leodice Savigny. Leodice stigmatura Verrill. Leodice stigmatura Verrill, 1900, pp. 641-643. Collected in tidepool on Nonsuch Island, Bennuda, April 23, 1929, Cat. No. 2,945. Leodice culebra Treadwell. Leodice ( Eunice ) culebra Treadwell, 1901, p. 197, fig. 37. Dredged off Nonsuch Island, Bermuda, 2 fathoms, Nov. 4, 1931, Cat. No. 312,339. Leodice mutilata Webster. Leodice ( Eunice ) mutilata Webster, 1884, pp. 315-316, pi. 9, figs. 36-40. Collected in coral, Castle Harbor, Bermuda, May 1929. Family Syllidae. Autolytus Clrube. Autolytus bidens sp. nov. (Text-figure 9). In a bottle labeled “luminous worms, from Castle Harbor, Bermuda” were numerous frag- ments of an Autolytus that is evidently of a new species. No entire individuals wrere present and I have no information concerning absolute size or differences in body regions. The prostomium (Text-fig. 9), is broader than long, its posterior margin deeply indented and almost its entire dorsal surface taken up by the eyes of which the anterior pair is the larger. They are dark brown in color and very conspicuous. The median tentacle is from six to eight times as long as the prostomium, lateral tentacles much shorter and a little more slender. Tentacular cirri about as long as the median tentacle. The first few dorsal cirri are long, later ones shorter but all longer than body width. Width of prostomium about 2/3 mm. The pharynx extends through six somites, the brown oesophagus through two, the stomach through seven. In the type the first twenty-one somites have only compound setae while later ones have in addition a tuft of long and extremely slender simple ones. With the appearance of the longer setae the antero-postero diameter of the parapodia increases, giving them a swollen appearance. There was no indication of sex products. The compound setae are veiy small, the basal joint slightly widened and beveled at the end. 1941] Treadwell : Polychaetous Annelids from Bermuda Plankton 29 The terminal joint is extremely short and has a terminal tooth and a smaller one at about the middle of the concave surface. Collected at surface, Nonsuch Island, Bermu- da, Nov. 16, 1931. Type, No. 312,351, Depart- ment of Tropical Research, New York Zoological Society. Haplosyllis Langerhans. Haplosyllis gula Treadwell. Haplosyllis gala Treadwell, 1924, pp. 11, 12, figs. 19-23. Dredged in shallow water, Isle de Gonave, Haiti, June 1, 1927, Cat. No. 272. Family Amphictenidae. Pectinaria Lamarck. Pectinaria gouldii Verrill. Pectinaria gouldii Verrill, 1873, p. 612, figs. 87, 87a. Collected in Castle Harbor, Bermuda, Nov. 2, 1931, 2 fathoms, Cat. No. 312,342. Family Opheliidae. Ammotrypane Rathke. Ammotrypane bermudiensis Treadwell. Ammotrypane bermudiensis Treadwell, 1936, pp. 60, 61, figs. 24-26. Collected at surface off Nonsuch Island, Bermuda, May 12, 1931, Cat. No. 317. Speci- mens dredged at 2 fathoms, off Nonsuch Island, Bermuda, Aug. 25, 1931, Cat. No. 311,675, and Oct. 3, 1931, Cat. No. 312,234. Family Glyceiiidae. Telake Chamberlin. Telake epipolasis Chamberlin. Telake epipolasis Chamberlin, 1919, pp. 346- 348, pi. 63, figs. 4-8; pi. 64, fig. 1. Collected at Bermuda, Net 1,179, surface, Aug. 14, 1931, Cat. No. 311,287. Family Terebellidae. Eupolymtiia Verrill. Eupolymnia magnified Webster. Eupolymnia ( Terebella ) magnified Webster, 1884, p. 324, pi. 11, figs. 58-60. Collected in Bermuda as follows: Nonsuch Island, tidepools, Apr. 23, 1929, Cat. No. 2,945A; Nonsuch Island, tidepools, Aug. 22, 1929, Cat. No. 29,158; surface at night, near Nonsuch Island, Sept. 13, 1931, Cat. No. 311,996. Family Sabellidae. Dasychonopsis Bush. Dasychonopsis conspersa Ehlers. Dasychonopsis ( Dasychone ) conspersa Ehlers, 1887, pp. 226-270, pi. 54, figs 1-6. From bottom of old barge, Bizoton, Port-au- Prince Bay, Haiti, Cat. No. 27,212. Family Serpulidae. Spirobranchus Blainville. Spirobranchus tricornis (Morch) Ehlers. Spirobranchus tricornis Ehlers, 1887, pp. 292- 295; pi. 57, figs. 8-15. Collected at Lamentin Reef, Port-au-Prince Bay, Haiti, Apr. 26, 1927, Cat. Nos. 27,379, 27,385, color red with golden setae. Bibliography. Chamberlin, R. V. 1919. The Annelida Polychaeta. Memoir Mu- seum. Comparative Zoology, Harvard College, vol. 48, pp. 1-514, pis. 1-80. Ehlers, Ernst 1864-1868. Die Borstenwiirmer, pp. 1-722, pis. 1-24. 1887. Florida Anneliden. Memoir Museum Com- parative Zoology, Harvard College, vol. 15, pp. 1-335, pis. 1— 60. Fauvel, Pierre 1916. Residtats des Campagnes Scientifiques ac- complies sur son yacht par Albert ler, Prince Souverain de Monaco. Fasc. 48, pp. 1-152, pis. 1-9. Grube, A. E. 1856. Annulata Oerstediana. Vitensk. Meddel. fra d. Naturh. Foren. Kjobenh., pp. 44-62. Horst, R. 1912. Polychaeta errantia. Siboga Exp. Mono- graphs, vol. 24A, 43 pp., 10 pis., pt. 1, Amphinomidae. Kinberg, J. G. H. 1857. Ofversigt. K. Vetensk. Akad. Forh., pp. 11- 14. 1865. Ofversigt. K. Vetensk. Akad. Forh., pp. 167— 180. McIntosh, W. C. 1885. Challenger Expedition Reports, vol. 12, pp. i-xxxvi, 1-554, pis. 1-55, 1A-39A. 1908-1910. Monograph of the British Annelids, vol. 2, Ray Society Publication, Nephthy- didae to Ariciidae, pp. 1-524, pis. 43-87. 1922. Monograph of the British Annelids, vol. 4, Ray Society Publication, Hermellidae to Sabellidae, pp. 1-250, pis. 112-127. 30 Zoologica: New York Zoological Society [XXVI: 7 Moore, J. Percy 1909. Polychaetous annelids from Monterey Bay and San Diego, California. Proc. Acad. Nat. Sci., Philadelphia, vol. 61, pp. 235- 295, pis. 7-9. 1911. Polychaetous annelids dredged by U. S. S. Albatross off the coast of Southern Cali- fornia in 1904. Ill, Euphrosynidae- Goniadidae. Proc. Acad. Nat. Sci. Phila- delphia, vol. 63, pp. 234-318, pis. 15-21. Munro, C. C. A. 1933. Polychaeta errantia collected by Dr. C. Crossland at Colon, in the Panama region and the Galapagos Islands. Proc. Zool. Soc. London, pt. 1, pp. 1-96, figs. 1-36. 1933 A. Polychaeta sedentaria collected by Dr. C. Crossland at Colon, the Panama region and the Galapagos Islands. Proc. Zool. Soc. London, pt. 4, pp. 1039-1092, figs. 1-31. Schmarda, Ludwig 1861. Neue wirbellose Thiere. Bd. 1, Hft. 2, pp. 1-164, pis. 16-37. Treadwell, A. L. 1901. Polychaetous annelids of Porto Rico. Bull. U. S. Fish Comm, for 1900, vol. 2, pp. 181-210, 81 figs. 1906. Polychaetous annelids of the Hawaiian Islands. Bull. U. S. Fish Comm, for 1903 pt. 3, pp. 1145-1181, 81 figs. 1924. Polychaetous annelids collected by the Barbados- Antigua Expedition from the University of Iowa in 1918. Univ. of Iowa Studies in Natural History, vol. 10, no. 4, pp. 1-23, 2 pis. 1928. Polychaetous annelids from the Arcturus Oceanographic Expedition. Zoologica, vol. 8, no. 8, pp. 449-485, figs. 177-179. 1936. Polychaetous annelids from the vicinity of Nonsuch Island, Bermuda. Zoologica, vol. 21, pt. 1, pp. 49-68, pis. 1-3. 1937. Polychaetous annelids from the West Coast of Lower California, the Gulf of California and Clarion Island. Zoologica, vol. 22, pt. 2, pp. 139-160, 2 pis. Verrill, A. E. 1873. Invertebrate Animals from Vineyard Sound. Report U. S. Fish Comm, for 1872, Annelids, pp. 580-622, pis. 10-17. 1900. Additions to the Turbellaria, Nemertina and Annelida of the Bermudas. Trans. Conn. Acad. Sci., vol. 10, (annelids), pp. 598-669. Webster, H. E. 1884. Annelida from Bermuda. Bull. U. S. Nat. Mus., 25, pp. 305-327, 12 pis. 1941] Hollister: Caudal Skeleton of Bermuda Shallow Water Fishes 31 8. Caudal Skeleton of Bermuda Shallow Water Fishes. V. Order Percomorphi: Carangidae.1 Gloria Hollister Department of Tropical Research (Text-figures 1-20). Outline. Introduction PAGE . . 31 Key Opposite page 32 Bermuda Percomorphi Carangidae Decapterus macarellus 32 Decapterus punctalus 33 Trachinotus palometa . 34 Trachinotus goodei 35 Argyreiosus vomer 37 Trachurops crumenophthalma 38 Chloroscombrus chrysurus 39 Caranx ruber 42 Caranx bartholomaei 42 Caranx crysos 43 Caranx latus 43 Summary 44 Introduction. This is the fifth of a series of papers dealing with the caudal skeleton of Bermuda fishes. The Carangidae of Bermuda is represented by six genera and twelve species. No specimens are available of Caranx guara, considered uncommon in Bermuda, either in the collection of this de- partment or in the collections of several other institutions. Caranx guara, locally known as “Gwelly,” is seen by fishermen in shallow water but is said to be a shy, wary fish. This paper deals principally with the adult fishes, as is the case with the four preceding studies of this series, but when young stages were available these were included. The length of specimens in this paper is stand- ard length unless otherwise stated. For caudal fin terminology, general bibliog- raphy, and method of preparing specimens for this study, refer to Part I. The symbols used in the figures are EP, epural; HS, haemal spine; 1, 2, 3, 4, 5, hypurals; IHS, interhaemal spine; INS, interneural spine; NS, neural spine; UN, uroneural; UR, urostyle. 1 Contribution No. 615, Department of Tropical Re- search, New York Zoological Society, Contribution from the Bermuda Biological Station for Research, Inc. We are indebted to the American Museum of Natural History for three specimens of Argy- reiosus vomer. I take this opportunity to thank Dr. William Beebe, Director of this Department, and Mr. John Tee-Van, General Associate, for their cooperation. The drawings are by Miss Janet B. Wilson, who kindly volunteered to do this work. In Bermuda Carangidae several precaudal vertebrae are neither typical trunk nor typical caudal in structure. In all species these verte- brae have ribs (although in several specimens diminutive) , which is characteristic of the typical trunk vertebrae. Closed haemal arches are also present, a typically caudal character. These precaudals include several modified vertebrae which immediately precede the true caudal. The structure of the precaudal haemal arch in Trachurops differs radically from that of Chloro- scoitibrus and Caranx and is readily distinguished from these two latter species by the crescent- shaped arch. In Decapturus macarellus and Decapterus punctatus several precaudals and anterior true caudals are crescent-shaped and arise on the anterior half of their centra. Decapturus is the only species in this study which has the anterior true caudal haemal processes crescent-shaped. It is of interest to note that the Bermuda Synodontidae is also unlike the families studied in Parts I, II and IV in having several vertebrae in the precaudal region which deviate from the typical trunk and caudal forms. In Synodontidae there are present, between the trunk and caudal, vertebrae lacking ribs (ribs being characteristic of the trunk), and also lacking closed haemal arches with spines, this structure being charac- teristic of the caudal. In Bermuda Carangidae there is also this devi- ation from what is generally designated typical trunk and typical caudal vertebrae. This differ- ence is found in several precaudal haemals which 32 [XXVI: 8 Zoologica: New York Zoological Society have closed arches typical of the caudal region but lack the haemal spine which is typical of the trunk. Because of these differences the term precaudal centra is used as in Synodontidae. The key is based on characters of the adult. In this respect it is important to mention, as an example, that in the immature specimen of Chloroscombrus chrysurus, 6 mm., the difference in length of the three short posterior neural and haemal spines and the length of the preceding long pair of spines is not pronounced as it is in the adult. In the mature specimen both the difference in length and shape is conspicuous and is considered a key character. 1. Decapterus macarellus (Cuvier & Valenciennes). (Text-figure 7). Diagonostic Characters: 1 interneural and 1 interhaemal arising over the 4th vertebra anterior to the urostyle. The horizontal length of this posterior inter- neural and interhaemal about one and a half times longer than the anterior oblique part. Haemal base of first anterior caudal lunar- shaped. Caudal interneurals and interhaemals more slender than in the other genera. Third stout posterior neural and haemal spines dagger-shaped and extend obliquely over three quarters of the following vertebra. Material Studied. The following description is taken from one specimen caught in Bermuda, Cat. No. 9,139, KOH Cat. No. 604, length 140 mm. Caudal Osteology. Urostyle: The urostyle is conical in shape. The posterior end appears to be consolidated on the dorsal surface with the base of the uroneurals and the fifth hypural and on the ventral with part of the base of the first and second hypurals. The anterior part of the urostyle is identical in form and size with the adjacent posterior part of the penultimate centrum. Uroneurals: There is one pair of uroneurals. These paired bones extend from the anterior margin of the urostyle to the distal margin of the hypural complex. On dissecting away the caudal rays the dorsal tip appears distinct from the tip end of the fifth hypural with which the uroneurals are fused. Text-figure 9 of a 10 mm. Decapterus punctatus shows the small fifth hypural in relation to the undeveloped uroneurals. Both these bones are only slightly ossified. Where young speci- mens of Carangidae were available for study this same relation of the two bones is found. Text- figures 13, 16, 17 and 18. Hypurals: In this adult specimen there appear to be four hypural bones; two below and two above the median line. In the 10 mm. Decapterus punctatus, Text-figure 9, the large dorsal hypural is divided almost to the distal margin, indicating that in a slightly younger specimen this single bone of the adult is formed by two separate elements. This condition is found in several other young carangids. Text-figures 16, 17. The first and fifth hypurals are almost identical in size and are complimentary in their distal positions in the marginal complex. The two large median hypurals of the adult are completely separate to the anterior rounded ends which are partly covered by the base of the uroneurals and the projected lateral muscle attachment process of the first hypural. The fifth or dorsal-most hypural is recognized in the adult by the pointed tip adjacent to the end of the fourth hypural. For its entire length, with the exception of this tip, the fifth hypural is fused with the uroneurals, and appears as one with these bones. Younger specimens give the true explanation of the de- velopment and relationship of the fifth hypural and the uroneurals. In the 42 mm. specimen of Decapterus punctatus the fifth hypural is more easily distinguished by the prominent line of junction which is still present between the hy- pural and the uroneurals. Decapterus macarellus. Tail of 140 mm. specimen showing especially the prolonged pos- terior interneural and interhaemal spines. X 3.52. 1941] Hollister: Caudal Skeleton of Bermuda Shallou > Water Fishes 33 Epurals: There are two epurals. The posterior bone is slender and rod-like and slants obliquely forward and downward from the distal caudal margin to the dorsal edge of the uroneurals. The ventral tip is inserted between the two lateral uroneural bones. The anterior epural is wider than the ventral epural throughout the entire length. Anteriorly, a long finger-like projection extends forward and fills the area above the re- duced neural process of the last centrum. Similar to the smaller epural, part of the ventral tip is inserted between the uroneural bones. Additional Characters Worthy of Note: This is the only genus of Bermuda Carangidae which has the extremely long and slender posterior inter- neural and interhaemal spines. The anterior and median ends arise near the anterior zygapophyses of the fourth vertebra from the urostyle and the bones extend back and toward the centra almost to the posterior margin of the next centrum. The interneurals and interhaemals, preceding the prolonged posterior pair, are more slender than in the other species studied in this paper. The precaudal haemal processes and also the first caudal haemals are lunar-shaped and placed on the anterior part of the centra. This develop- ment is similar to Decapterus punctatus. 2. Decapterus punctatus (Agassiz). (Text-figures 8, 9). Diagnostic Characters: 2 interneurals and 2 interhaemals arising over the 4th vertebra anterior to the urostyle. The horizontal length of this posterior pair only a little longer than the anterior oblique part. Haemal base of first anterior caudal lunar- shaped. Caudal interneurals and interhaemals not as slender as those of Decapterus macarellus. Dorsal and ventral fin rays not as slender as those of Decapterus macarellus. Material Studied. The following description is taken from three specimens caught in Bermuda, Cat. No. 8,968, KOH Cat. No. 2316, length 10 mm.; KOH Cat. No. 340, length 18 mm.— taken from under a jellyfish; KOH Cat. No. 2315, length 42 mm. Caudal Osteology. Urostyle: In the 42 mm. specimen the urostyle is conical in shape and similar to Decapterus macarellus. No definite posterior tip can be seen. In the 10 mm. specimen the upturned posterior end of the urostyle extends beyond the basal end of the fifth hypural. The anterior margin is iden- tical in form with that of the preceding centrum but posteriorly the shape changes radically into a long slender upturned structure. The urostyle is slightly ossified as far as the base of the fifth hypural. Here, there is a heavy line across the urostyle and beyond this there is little ossifica- tion. Uroneurals: As in Decapterus macarellus, there is a single pair of uroneurals and in the 42 mm. specimen these paired bones are similar in shape and position to those of the above species. In Decapterus punctatus the line of junction between the fifth hypural and the uroneurals is distinct but this has disappeared in the older specimen of the other species. In the 10 mm. Decapterus punctatus the uroneurals are long, slender, curved bones which extend from the hypural margin to the anterior part of the urostyle. Throughout their entire length the uroneurals are separate from the urostyle and the fifth hypural. Text-figure 8. Decapterus punctatus. Tail of 42 mm. specimen showing the difference between this species and Decapterus macarellus in the arrangement and proportions of the interneural and interhaemal spines of the posterior groups. X 9.65. 34 Zoologica: New York Zoological Society [XXVI: 8 Decapterus punctatus. Tail of 10 mm. specimen. This stage shows the development of the 3rd and 4th hypurals which are fused in the 42 mm. specimen. The fifth hypural and the uro- neurals are separate bones in this stage. X 45.4. Hypurals: In the 42 mm. specimen there ap- pears to be four hypurals; two below and two above the median line. In the 10 mm. specimen there are three hypural bones above the median line, which indicates that the large dorsal hypural of mature specimens is a combination of two bones. Also this young specimen has a small slit in the base of the second hypural which probably indicates a one-time ancestral division of this other large hypural bone. In all Bermuda Isospondyli and Iniomi there are at least three hypurals below the median line. In general shape and proportions the hypural complex of the adult Decapterus punctatus resembles that of Decapterus macarellus, with the exception of the identity of the fifth hypural and uroneurals. Epurals : There are two epurals in the adult, as in Decapterus macerellus, and the shape and pro- portions are similar. In this species the ventral ends are not inserted between the uroneural bones, but this may be an age character. There is no trace of the epurals in the 10 mm. specimen. Additional Characters Worthy of Note: The posterior pair of interneural and interhaemal spines are conspicuously longer than the preced- ing spines and the oblique part extends posterior- ly for almost the length of the following centrum. This pair is not as long nor as slender as the corresponding pair of Decapterus macarellus. The precaudal haemal processes and also the first caudal haemals are lunar-shaped and placed on the anterior part of the centra. In the 10 mm. specimen the caudal centra are only moderately spool-shaped and the zyga- pophyses and the neural and haemal processes are undeveloped. The neural and haemal proc- esses are simple, slender bones and there is little differentiation in the development of the four anterior pair of spines. This difference is con- spicuous in the_adult. 3. Trachinotus palometa Regan. (Text-figure 10). Diagnostic Characters: 1 long and slender interneural and 1 inter- haemal arising over the 4th vertebra anterior to the urostyle. 17 interneurals in the caudal region. Bases of haemal processes arising at the center of the centra. No short or stout posterior neural and haemal spines. Material Studied. The following description is taken from one specimen caught in Bermuda, KOH Cat. No. 601, length 119 mm. Caudal Osteology. Urostyle: The anterior part of the urostyle is identical in size and shape to the adjacent part of the preceding penultimate centrum. The pos- terior end cannot be seen because it is consoli- dated with the bases of the uroneurals and hypurals. The dorsal surface is covered by the uroneurals and the ventral surface by the hypural bases. Uroneurals: There appears to be a single pair of uroneurals, the bones of which extend from the anterior dorsal edge of the urostyle to the distal margin of the hypurals. For part of the distal length the line of junction between the fifth hypural and the uroneurals is distinct. In the smaller specimen of Trachinotus goodei these bones appear separate. Hypurals: In this adult specimen there appear to be four hypural bones; two below and two above the median line. The second large hypural below the median line is solid with the exception Hollister: Caudal Skeleton of Bermuda Shalloiv Water Fishes 35 1941] of a small oblong hole near the base. In Tra- chinotus goodei of 54 mm. in length, the base is divided and a definite line can be seen which extends for half the length of the hypural bone. In the large dorsal hypural of Trachinotus palometa there is also indication that this hypural was at one time divided because a distinct line extends anteriorly from the distal margin for more than three-quarters of the length of the hypural. In the other species the base of this large dorsal hypural is divided and a narrow slit extends for about one-quarter the length of the bone and does not quite join with the slit extend- ing from the distal margin. In the species under discussion the fifth or dorsal-most hypural is closely associated with the uroneurals but each can be identified at their dorsal extremity by distinct and separate pointed tips and a line which extends anteriorly for almost half the length. From here the two are fused. In the other species this fifth hypural is more distinct. Hypural numbers have been omitted from this illustration because of the inclusion of the caudal fin rays; for hypural reference, see Text-figure 11 of Trachinotus goodei. Epurals: There are three epurals in this species and genus. The anterior or first epural is the largest, which is true of the adults of all the other species treated in this paper. Anteriorly, there is a broad thin growth which ahnost fills the entire area dorsal to the penultimate centrum and the urostyle. The second and third epurals are long, slender bones and very closely associated. At both the proximal and distal ends the tips can be distinguished as separate bones. The ventral ends are not inserted between the uroneurals as is the case in Trachinotus goodei. Often this appears as a growth character but the specimen of this species is less than half the size of Tra- chinotus palometa and the tips of the former are inserted. Additional Characters Worthy of Note: The il- lustration of this species is the only one which includes the caudal fin rays because the variation in the count is slight in the other species of Carangidae and therefore of little importance. Here the count is : dorsal raylets 6 plus 1 1 dorsal rays, and ventral raylets 6 plus 9 ventral rays, making a total of 17 dorsal plus 15 ventral. 4. Trachinotus goodei Jordan & Evermann. (Text-figure 11). Diagnostic Characters: 2 broad interneural and interhaemal spines arising over the 5th vertebra anterior to the urostyle. 15 interneurals in the caudal region. Bases of the haemal processes arising on the anterior half of the centra. No short or stout posterior neural and haemal spines. Material Studied. The following description is taken from one Text-figure 10. Trachinotus palometa. Tail of 119 mm. specimen with three epurals. One interneural and one interhaemal spine is associated with the 4th vertebra from the urostyle. X 3.6. 36 [XXVI: 8 Zoologica: New York Zoological Society 4 3 2 Text-figure 11. Trachinotus goodei. Tail of 54 mm. specimen with three epurals and evidence of two pairs of uroneurals. Two interneurals and two interhaemals associated with the 5th vertebra from the urostyle. X 8.5. specimen caught in Bermuda, KOH Cat. No. 438, length 54 mm. Caudal Osteology. Urostyle: The anterior part of the urostyle is cone-shaped and its margin similar to the pos- terior part of the penultimate centrum. The reduced posterior tip of the urostyle is hidden and consolidated with the base of the uroneurals. The uroneurals protect the dorsal and posterior part of the urostyle and the bases of the hypurals abut its ventral and posterior surface. Uroneurals: These paired bones are unlike those of the other species studied in this paper. For a complete interpretation a series of younger specimens is needed. In this 54 mm. fish there are two pointed tips which form part of the hypural margin. Each represents paired lateral bones, the bases of which partly overlap the urostyle and the fifth hypural. The anterior dorsal uroneural extends from above the anterior margin of the urostyle where it is deep and wing- shaped and where bases of the epurals are inserted between its lateral bones. It extends posteriorly and dorsally and diminishes into a slender bone with a pointed distal tip. The second uroneural is similar distally but it arises immediately on the anterior part of the urostyle centrum. It overlaps the base and dorsal surface of the fifth hypural for all but the distal tip end. A broad, thin, paired bone covers part of the anterior half of the uroneurals and the fifth hypural. In our specimen of Trachinotus palometa of 119 mm. in length, only one pair of uroneurals can be found if the second pointed tip is to be interpreted as the fifth hypural. A series of young specimens is necessary in the case of both species to inter- pret adequately the development of this part of the hypural complex. Hypurals: There are two hypurals ventral and two dorsal to the median line. In the second large hypural there is definite evidence of a divi- sion of this bone, for there remains a suggestion of a double base with a line extending from here for half the length of the hypural. In none of the Bermuda carangids has this second hypural ap- peared as two separate bones, even in the very young of several species. This is the reason for consistently designating this particular hypural as a single bone. Its counterpart, the large hypural dorsal to the median line, has shown in several young specimens that it is formed by the fusion of two separate bones, which gives a cri- terion for calling this hypural three and four. In this specimen hypurals three and four are distinct both anteriorly and posteriorly and only a small area in the center has fused beyond iden- tity of the two separate bones. The fifth and most dorsal hypural is similar in size at its distal extremity to the first hypural and balances this bone in its position in the hypural fan. Its length, however, is less and the median end di- minishes to a wedge-shaped tip. Epurals: There are three epurals, which is also true of Trachinotus palometa. But in the species of this description the epurals appear more separate and individual than in Trachinotus palometa, which is a larger and older specimen. In this 54 mm. Trachinotus goodei the first or anterior epural is the largest, the second inter- mediate and the third, or posterior, the smallest. This is true of both their lengths and widths. The ventral ends are inserted between the lateral bones of the uroneurals. This is not so in the other species. 1941] Hollister: Caudal Skeleton of Bermuda Shalloic Water Fishes 37 5. Argyreiosus vomer (Linnaeus). (Text-figures 12, 13). Diagnostic Characters: The caudal skeleton is conspicuously deeper and relatively shorter than any of the other species treated. 3 anterior caudal haemal spines with triangular projections on the anterior surface at mid- length. 3 short posterior neural and haemal spines stout and club-like. Material Studied. This description is from a study of three speci- mens presented by the American Museum of Natural History. Cat. No. 14,184 from Pom- pano, Florida; KOH Cat. No. 2321, length 18 mm. Cat. No. 12,505 from Mastic, L. I.; KOH Cat. No. 2322, length 45 mm. Cat. No. 13,583 from Rio de Janeiro; KOH Cat. No. 2323, length 140 mm. Caudal Osteology. Urostyle: In the adult specimen of 140 mm. in length the posterior end of the urostyle is con- solidated with the dorsal bones and cannot be distinguished. In our young specimen of 18 mm. the urostyle extends dorsally to the hypural margin. An- teriorly, the urostyle is almost a perfect half centrum but at the base of the second hypural it turns abruptly and extends in an oblique-dorsal direction and becomes a slender tapering rod. At the basal tip of the fifth hypural a mark ap- pears which indicates consolidation in this youth- ful stage of the urostyle. The bases of all of the hypurals are separate from the urostyle with the exception of the fifth hypural whose anterior surface is in conjunction with the urostyle. Uroneurals: There is a single pair of uroneurals which are more distinct in the 18 mm. specimen than in the two older stages. In the smallest fish the anterior part is already enlarged and fills the area dorsal to the urostyle but the spool- shaped urostyle is distinct. In the largest speci- men the urostyle and the uroneurals have become one and there is only a suggestion of the urostyle as such. Both the anterior and the posterior portion of the uroneurals have increased in pro- portions. Distally, the uroneurals and fifth hypural have fused and there is only a suggestion of the hypural which in the 18 mm. specimen was a distinct bone. Hypurals: In the adult specimen there are four hypural bones, two below and two above the median line. In the 18 mm. fish it is clear that the large hypural dorsal to the median line is the result of the fusion of two bones. Truly young specimens would undoubtedly show this as they have in several other species in this paper. The dorsal, or fifth hypural, is distinct in the 18 mm. specimen but in the 140 mm. fish it has be- IHS Text-figure 12. Argyreiosus vomer. Tail of 140 mm. specimen. The bones of this deep-bodied fish are con- spicuously stout and the centra less elongate than in the other species. X 3.23. 38 Zoologica: New York Zoological Society [XXVI: 8 4 3 2 Text-figure 13. Argyreiosus vomer. Tail of 18 mm. specimen showing the posterior end of the urostyle, the uroneurals and the fifth hypural. These are not distinct in the 140 mm. fish. There is a hint of the division of the 3rd and 4th hypurals. X 25.2. come one with the uroneurals. The first hypural is not as massive as the corresponding bone in the adult, and there is a conspicuous large hole in the base or arch area. This is present in most of the neural and haemal bases but in the largest specimen the holes have disappeared in the three posterior processes and become smaller in the preceding arch bases. Epurals: There are two epurals. In the 18 mm. specimen their shape in general is similar with the exception of the anterior projection on the first bone, which is a growth character. In no respect do these two bones resemble one another in the 140 mm. specimen. The anterior projection from the base of the first epural has become solid and massive and fills the area above the reduced neural process of the penultimate centrum. The rod-like form of the young specimen has disap- peared entirely. The second or posterior epural has changed very little from that of the young stage. The ventral ends of both epurals in all three stages are inserted between the lateral bones of the uroneurals. Additional Characters Worthy of Note: As is typical of this deep bodied species, the inter- neural and interhaemal spines are massive in the adult specimen. In each there is a central shaft which is heavily ossified and has lateral projec- tions on the horizontal part. In the smallest specimen there is the beginning development of this projection and all other parts of these bones are only slightly ossified. Several anterior caudal haemal spines are unique in development as com- pared with the other Bermuda Carangidae. The first and second are usually stout and at mid- length their surfaces abut. The three following haemal spines are also stout and have on their anterior sides heavy triangular projections. These are present in all three stages. This is illustrated in the Key (Text-fig. 5). 6. Trachurops crumenophthaltna (Bloch). (Text-figure 14). Diagnostic Characters: The posterior group of two interneurals and two interhaemals associated with the fourth vertebra from the urostyle. The haemal processes of several precaudal centra are crescent-shaped and the spines arise on the anterior half of the centra. Material Studied. Three specimens were used for this description and all were caught in Bermuda. Cat. No. 9,140, KOH Cat. No. 615. Cat. No. 9,140, KOH Cat. No. 614, length 115 mm. Cat. No. 25,147, KOH Cat. No. 1135, length 108 mm. 1941] Hollister: Caudal Skeleton of Bermuda Shallow Water Fishes 39 Caudal Osteology. Urostyle: In all specimens studied the posterior end of the urostyle is embedded in the terminal bones. The bases of the uroneurals and the hypurals surround this area. The anterior part of the urostyle is almost a perfect half centrum in shape and size. The dorsal surface is covered by the heavy uroneurals and the ventral surface by the base of the first hypural . Uroneurals: There appears to be but a single pair of uroneurals. In our adult specimens these paired bones are massive and extend obliquely backward and dorsally from above the anterior part of the urostyle to the distal margin of the hypurals. In the anterior area a small portion of the ventral ends of the epurals are wedged be- tween the lateral bones of the uroneurals. The oblique distal part probably represents the fifth hypural fused with the uroneurals. Our material is too advanced in development to illustrate this fact, which is found in the young specimens of the closely related genera. Hypurals: Our material shows two hypurals ventral to and two dorsal to the median line. The central bones are large and fan-shaped, which is characteristic of this family. Young specimens would undoubtedly show that the large dorsal hypural was formed by the fusion of two bones and also that the fifth hypural was separate. In these adult specimens the fifth hypural is fused with the uroneurals and not distinguishable from them. On the basis of repeated evidence in the young of several closely related genera the hy- purals are considered as five, which is seen in the Text-figure 14. Epurals: The two epurals fill the area above the penultimate centrum and the urostyle. The long projection of the first epural extends an- teriorly above the reduced neural process of the penultimate centrum. The base is inserted be- tween the uroneurals. The second or posterior epural is long and slender and slightly enlarged at the ventral end, which lies between the uro- neurals. 7. Chloroscotnbrus chrysurus (Linnaeus). (Text-figures 15-18). Diagnostic Characters: 26 or 27 interhaemals in the caudal region. 6 interhaemals between the first and second anterior caudal haemal spines. Material Studied. The following description is based on seven specimens taken in Haiti. Cat. No. 6,842, KOH Cat. No. 2317, lengths 100 mm. and 80 mm. Cat. No. 7,183, KOH Cat. No. 2318, lengths 15, 10, 7.5, 6.5, 6 mm. Caudal Osteology. Urostyle: Four stages of development were found in specimens of 6 mm., 10 mm., 15 mm., and 100 mm. in length. In the largest fish, which is fully ossified, the posterior end of the urostyle is completely hidden by the overlapping uroneurals and hypurals. As in the other Bermuda Carangidae the anterior part of the urostyle is almost a complete half centrum and is similar in proportions to the adjacent part of the preceding centrum. In the 6 mm. specimen the urostyle is a long, slender, rod-like structure which extends from the posterior margin of the penultimate centrum to the distal margin of the hypurals. Anteriorly, the proportions are similar to the adjacent part of the preceding centrum. The urostyle extends posteriorly in an oblique and dorsal direction, tapering to about one-half the depth. The ossification is delicate through- out and ends midway between the bases of the fourth and fifth hypurals. A cartilaginous rod INS Text-figure 14. Trachurops crumenophthalma. Tail of 115 mm. specimen showing two interneurals and two interhaemals associated with the 4th and 5th vertebrae from the urostyle. X 11.65. 40 Zoologica: New York Zoological Society [XXVI: 8 INS Text-figure 15. ■ Chloroscombrus chrysurus. Tail of 100 mm. specimen showing the 3rd and 4th hypurals fused and the 5th hypural united with the uroneurals. X 33.3. extends from here and disappears in the bases of the caudal rays. In the 10 mm. specimen ossi- fication is more pronounced and the posterior dorsal end is seen at the center of the base of the fourth hypural. Anteriorly, the shape has begun to resemble that of the adult. The 15 mm. specimen shows still greater ossification and con- solidation. Uroneurals: There is a single pair of uroneurals, which in the adult is indicated only at the distal end. These bones have become fused with the fifth hypural in the largest specimen. The three younger stages show clearly the development of the uroneurals. In the 6 mm. specimen this paired bone extends dorsally above the urostyle from the region of the second hypural to the margin of the hypurals. It is long and slender and the anterior end is slightly larger than the posterior tip. It is of importance to note the relation of this bone to the others and its inde- pendent position, which is found only in the very young stages. Chloroscombrus chrysurus. Tail of 6 mm. specimen which is partly ossified. There are no interneurals or interhaemals or epurals. The 3rd, 4th and 5th hypurals and the uroneurals are separate bones. The urostyle extends into the hypural margin. X 104. 1941] Hollister: Caudal Skeleton of Bermuda Shallow Water Fishes 41 Text-figure 17. Chloroscombrus chrysurus. Tail of 10 mm. specimen showing increased ossification. The centra are spool-shaped and the epurals, uroneurals and base of the interneural and interhaemal spines have appeared. The 3rd and 4th hypurals have begun to fuse and the uroneurals abut the fifth hypural. X 83. In the 10 mm. specimen the uroneurals have increased anteriorly both in depth and length and almost reach the anterior margin of the uro- style. The shape of this end has changed from a blunt rounded tip to a deeper indented form. The posterior part is reduced and the distal end appears in conjunction with almost half the proximal length of the fifth hypural. In this region the uroneurals have grown over the uro- style. The anterior part is still separate from the urostyle. In the 15 mm. specimen the uroneurals re- semble the structure of the adult more than the 10 mm. specimen, and the shape and proportions are similar. The base of the uroneurals has fused with the dorsal surface of the urostyle and in only one place is there any indication of the youthful stage where all the under part of this bone was entirely separate. There still remains two perforations or unossified areas. The ante- rior part of the uroneurals abut the reduced neural process of the penultimate centrum and extend dorsally almost to the distal margin of the fifth hypural. In this stage the uroneurals have be- come entirely consolidated with the dorsal surface of this fifth hypural. Hypurals: In the adult 100 mm. specimen there are two hypurals below and two above the median line. The first and fifth hypurals are the same size distally and flank the ventral and dorsal part of the hypural fan. Two large hypurals form the central part of the hypural complex ; one below and one above the median line. From a study of the young specimens it is certain that the large dorsal hypural is formed by the fusion of two bones and that the fifth hypural has fused with the uroneurals. In the 6 mm. specimen, which is the youngest stage available for study of the Bermuda Caran- gidae, there are five distinct hypural bones. The first, or anterior bone, is long and slender and slightly enlarged at the median base. This base, which is the haemal arch, develops rapidly in the 10 mm. and 15 mm. stages. In the smaller fish a square, wing-like growth projects ante- riorly and abuts the haemal process of the pre- ceding centrum and there is a large hole or unossified area in the center of this growth. In this stage the lateral ridge, for the muscle attach- ment, is a small triangular projection from the base and overlaps slightly the base of the second hypural. In the 10 mm. specimen this ridge has more than doubled in size and proportion. The first hypural of the 15 mm. specimen resembles the corresponding bone of the adult fish with the exception of the density of ossifica- tion, and extent of development of the muscle attachment process, and proximity to the ventral surface of the urostyle. There is still considerable space between the haemal arch and the urostyle, 42 Zoologica: New York Zoological Society [XXVI: 8 which entirely disappears in the adult specimen. This is also true of the preceding haemal arches. The second hypural changes less in shape and proportions than any of the other hypural bones. In the 6 mm. specimen the base is divided into two by a long oval slit which extends for about one-quarter the length of the bone. In the 10 mm. specimen the two bases have fused but a small oval hole remains. In the 15 mm. fish there is no indication of either the two bases or the slit of the younger stages. The third and form part of the caudal margin. In the 15 mm. specimen the degree of ossification is identical with the other caudal bones. The shape of both epurals is similar to that of the adult, and the median ends are ir erted between the uroneurals, which is also an adult character. Additional Characters Worthy of Note: The illustrations show the increase in ossification with age and also the change in shape and pro- portions of all of the caudal bones. In the 6 mm. specimen there is no evidence of epurals, inter- Text-figure 18. Chloroscombrus chrysurus. Tail of 15 mm. specimen. The posterior end of the urostyle is reduced and the distal portion of the uroneurals flank the side of the 5th hypural. In the 100 mm. specimen these two bones have fused. X 42. fourth hypurals are separate bones in the young- est stage and in the 10 mm. specimen their distal margin has fused and the space between become less. The 15 mm. fish still lias two bases which represent the two separate bones of the younger stage but the slit between has diminished by more than half its former length. In the 100 mm. specimen there is no trace of a slit or double base. The fifth hypural appears as a very small wedge-shaped bone between the distal end of the urostyle and the fourth hypural . Its growth and development from this stage to the adult is remarkable and without several very young specimens this hypural would not be identified as an hypural bone. In the youngest stage this bone is entirely separate from the surrounding structures. In the 10 mm. fish the bone has in- creased in length and depth and about one-lialf of its anterior length abuts the uroneurals on the dorsal surface. In the 15 mm. specimen the length is greatly increased and all but a small part of the dorsal end is in conjunction with the uroneurals. The adult specimen of 100 mm. shows that the fifth hypural and the uroneurals have fused and all that remains of their separate identity is a light line at the distal extremity. Epurals: There are two epurals in this species. Neither of these bones can be found in the 6 mm. fish. In the 10 mm. specimen these epurals appear with delicate ossification and as long slender bones. The anterior epural is longer and broader than the second one and has the be- ginning of the anterior projection near the median end. Both bones are free and their distal tips neurals and interhaemals. The centra are rectangular in shape with considerable distance between their margins. In the 10 mm. specimen the spool-shape of the centra begins to change and to resemble the adult. The epurals are lightly ossified and also the interneurals and interhaemals. The zygapophyses are present on the dorsal and ventral surfaces of the centra. With the consolidation from a long rectangular structure to a shorter spool-shaped centra the neural and haemal processes appear to shift from their youthful anterior position to a central position. The three reduced posterior neural and haemal spines of the adult are simple and unmodified in the 6 mm. and 10 mm. specimens. 8. Caranx ruber (Bloch). (Text-figure 19). 9. Caranx bartholomaei Cuvier & Valenciennes Diagnostic Characters (both species) : Total of 24 interhaemals in the caudal region. Total of 22 interneurals in the caudal region. 4 interhaemals between the first and second anterior caudal haemal spines. 3 interneurals and 3 interhaemals in posterior group in three specimens. The oblique part more slender than in the two following species. Minor species differences cited in Key and in text. 1941] Hollister: Caudal Skeleton of Bermuda Shallow Water Fishes 43 Material Studied. Caranx ruber; one specimen taken in Haiti. Cat. No. 7,016, KOH Cat. No. 2320, length 160 mm. Caranx bartholomaei; two specimens caught in Bermuda. Cat. No. 25,057, KOH Cat. No. 1074, length 50 mm. Cat. No. 25,065, KOH Cat. No. 1073, length 52 mm. Caudal Osteology. Urostyle: The reduced terminal end is hidden in both species by the heavy uroneurals on the dorsal and the base of the hypurals on the ventral surface. No small specimens are available to show the development. The anterior part is cone-shaped and of the same proportions as the posterior half of the penultimate centrum. The dorsal surface is covered by the uroneurals and the ventral by the first hypural in Caranx ruber (Text-fig. 19). In Caranx bartholomaei, which is one-third the length, the base of the first hypural is still separate from the ventral surface of the urostyle. Uroneurals: In the 50 mm. specimen of Caranx bartholomaei there is indication of one pair of uroneurals. At the distal end the line of junction between the uroneurals and the fifth hypural still remains. There is no evidence of this in the 160 mm. specimen of Caranx ruber. In this species the two bones have fused. Hypurals: In both species there are two hy- purals which are ventral to and dorsal to the median line. Their positions and proportions are similar in the corresponding bones. Because of facts presented by several young stages in closely related genera in this family, the hypural bones of these species are numbered 1 to 5 in the illustration. Epurals: There are two epurals in both species and the corresponding bones are similar in shape and position. In the distal dorsal portion of the smaller Caranx bartholomaei the epurals are more slender. This has been found to be an age character in other genera. Additional Characters Worthy of Note: In Caranx ruber the posterior neural zygapophyses have hook-like projections on the dorsal surface. This is shown in the anterior vertebra in the illustration. The development is especially prominent in the central caudal area. In Caranx bartholomaei the dorsal surfaces of the corre- sponding zygapophyses are smooth. There is also a difference in the development of the anterior neural zygapophyses of the two species. In Caranx ruber the surfaces are jagged and notched, especially in the central caudal area, but this is not true in Caranx bartholomaei. In a detailed study of the two species many minor differences such as these distinguish each as a different species. 10. Caranx crysos (Mitchill). 11. Caranx latus Agassiz. (Text-figure 20). Diagnostic Characters (both species) : Total of 17 to 20 interhaemals in the caudal region. Total of 15 to 18 interneurals in the caudal region. 3 interhaemals between the first and second anterior caudal haemal spines. 2 interneurals and 2 or 3 interhaemals in the posterior group in the five specimens studied. The oblique part broader than in the two preceding species. Minor species differences are cited in the Key and in the text. Text-figure 19. Caranx ruber. Tail of 160 mm. specimen. This figure represents both this species and Caranx bartholomaei which in gross structure are similar. X 2.74. 44 Zoologica: New York Zoological Society [XXVI: 8 INS Text-figure 20. Caranx latus. Tail of 87 mm. specimen. This figure represents both this species and Caranx crysos, the gross structure being similar. X 15.87. Material Studied. Caranx crysos; one specimen taken in Haiti. KOH Cat. No. 2319, length 130 mm. Caranx latus; four specimens caught in Bermu- da. KOH Cat. No. 1070, length 44 mm. KOH Cat. No. 412, length 63 mm. KOH Cat. No. 649, length 80 mm. KOH Cat. No. 1040, length 87 mm. Caudal Osteology. Urostyle: The anterior part of the urostyle in both species is cone-shaped and almost identical in shape with the posterior half of the preceding centrum. The dorsal surface is fused with the bases of the uroneurals and the ventral surface with the base of the first hypural. The posterior end cannot be distinguished in specimens as old as those in this collection. Text-figure 20 repre- sents both species. Uroneurals: In the 87 mm. specimen of Caranx latus one pair of uroneurals is found where it has fused during growth with the fifth hypural. In Caranx crysos, which is 130 mm. in length, there is no evidence left and the fifth hypural and uroneurals appear as one structure. Hypurals: In both species there are two hy- purals below and two above the median line. They are similar in proportions and arrangement to the other species of Caranx. None of these specimens are young enough to show the develop- ment and eventual fusion of the hypurals but the figure is numbered to show the position of five hypurals which the young of closely related genera have demonstrated. Epurals: There are two epurals, as in all but one genus of Carangidae. In the distal portion of the smaller Caranx latus these bones are more slender than those of Caranx crysos. This de- velopment is correlated with age in other genera. Additional Characters Worthy of Note: In Caranx crysos there are 20 interhaemals in the caudal region and 18 interneurals. There are fewer in Caranx latus, which has 17 interhaemals and 15 or 16 interneurals in the caudal region. The shapes and proportions of the zygapophyses differ in the two species, also the presence and absence of neural and haemal arch perforations. In a detailed study of the minor differences in both species these can be distinguished as two separate species. Summary. The following facts correlate the salient simi- larities found in the study of Bermuda Caran- gidae. Vertebral count: 10 trunk plus 14 caudal in all species but Caranx crysos and Decapterus punc- tatus. These have 10 trunk and 15 caudal. In both, only one specimen was available for the count. Caudal fin count : There is only slight variation among the species. The illustration of Tra- chinotus palometa (Text-fig. 10) shows the ar- rangement. It is usually 6 raylets plus 11 rays dorsal; 6 raylets plus 9 rays ventral, making a total of 17 dorsal, plus 15 ventral. Epurals: There are two epurals in all but the genus Trachinolus, which has three. Hypurals: In the adults of all species there are four hypurals; two below and two above the median line. The two central bones are large and fan-shaped. The dorsal or fifth hypural is fused with the uroneurals in all adults. In the young stages it is separate. In young stages the large dorsal hypural is found to be formed by the fusion of two separate bones. There remains a hint in several of the young of a one-time division of the large ventral or second hypural. This is not complete in any specimens of this 1941] Hollister: Caudal Skeleton of Bermuda Shalloiv Water Fishes 45 family. In all Bermuda Isospondyli and Iniomi there are at least three hypurals below the median line. Uroneurals: In all species but Trachinotus goodei there is a single pair of uroneurals. Here there is a suggestion of a second pair, but young specimens are necessary to ascertain this fact. Elongate spines in caudal complex: In the adult of all species one long neural spine and two long stout haemal spines form the anterior part of the caudal complex. Anterior caudal haemals: Decapterus is the only genus in this series which has the bases of the first few anterior caudal haemals crescent- shaped and situated on the anterior half of the centra. The typical shape is triangular. Pre-caudal haemals : Decapterus and Trachurops have crescent-shaped precaudal haemal bases which are situated on the anterior half of the centra. Specialized neural process: Adult specimens of all species of Bermuda Carangidae have a reduced neural process on the penultimate centrum. The long anterior projection from the first epural extends into the area above this process. ISHES. GROUP I 3 posterior neural and mal caudal spines spicuously short or st 2 epurals. c A R A N G I D A Text-figure 1. Caranx ruber Posterior neural zygapophyses with hook- like projections on the dorsal surfaces, especially in the central caudal area. Anterior neural zygapophyses with notched dorsal surfaces especially in the central caudal region. -Group A interhaemals and 20 to 22 interneurals in caudal region. linterhaemals between the first and second ‘anterior caudal haemal spines. Caranx bartholomaei No hook-like projections on dorsal surfaces of posterior neural zygapophyses. Anterior neural zygapophyses with smooth dorsal surfaces. GROUP II No conspicuously short terior neural and h spines. 3 epurals. Caranx crysos 20 interhaemals and 18 interneurals in cau- dal region. -Group B to 20 interhaemals and 15 to 18 inter- neurals in caudal region, interhaemals between the first and second anterior caudal spines. Caranx latus 17 interhaemals and 15 or 16 interneurals in caudal region. KEY TO CAUDAL SKELETON OF BERMUDA SHALLOW WATER CARANGID FISHES. (Text-figs. 1-6). c A R A N G I D A E GROUP I 3 posterior neural and hae- mal caudal spines con- spicuously short or stout. 2 epurals. Text-figure 1. Decaptcrus macarellus 1 intemeural and 1 interhaemal arising over the 4th vertebra anterior to the urostyle. The horizontal part about one and a half times longer than the anterior oblique part. Sub-Group A Horizontal length of posterior inter- neural and inter- haemal conspicu- ously longer than the preceding spines. 1st anterior caudal haemal arch cres- cent-shaped and on anterior half of centrum. Text-figure 3. Decapterus punctatus 2 intemeurals and 2 interhaemals arising over the 4th vertebra anterior to the uro- style. The horizontal part only a little longer than the oblique part. Sub-Group B Horizontal length of posterior inter- neural and inter- haemal not con- spicuously long and the general shape the same as the spines im- mediately preced- ing. 1st anterior caudal haemal arch not crescent -shaped and on entire centrum. Division I Argyreiosus vomer 3 anterior caudal hae- mal spines with tri- angular projections at mid-length. Posterior vertebrae rel- atively shorter and more massive than in Division II. Sub-Division A Trachurops crumenophthalma Posterior group of intemeurals and inter- haemals associated with 4th vertebra from the urostyle. Precaudal haemal process crescent-shaped and on anterior half of centrum. Division II No triangular projec- tions on anterior caudal haemals. Posterior vertebrae rel- atively longer and more slender than in Division I. Group I Chloroscombrus chrysurus 26 or 27 interhaemals. 6 interhaemals between the first and second anterior caudal hae- mal spines. Sub-Division B Posterior group of intemeurals and inter- haemals associated with 5th vertebra from the urostyle. Precaudal haemal process triangular-shaped and covers all of centrum. GROUP II Trachinotus palometa No conspicuously short or stout pos- terior neural and haemal caudal spines. 3 epurals. 1 intemeural and interhaemal spine over the 4th vertebra from the urostyle. 17 intemeurals in caudal region. Trachinotus goodei 2 intemeural and interhaemal spines over the 5th vertebra from the urostyle. 15 intemeurals in caudal region. Group II Caranx Less than 26 interhaemals. 3 or 4 interhaemals between the first and second anterior caudal haemal spines. Caranx ruber Posterior neural zygapophyses with hook- like projections on the dorsal surfaces, especially in the central caudal area. Anterior neural zygapophyses with notched dorsal surfaces especially in the central caudal region. Sub-Group A 24 interhaemals and 20 to 22 intemeurals in caudal region. 4 interhaemals between the first and second anterior caudal haemal spines. Caranx bartholomaei No hook-like projections on dorsal surfaces of posterior neural zygapophyses. Anterior neural zygapophyses with smooth dorsal surfaces. Caranx crysos 20 interhaemals and 18 intemeurals in cau- dal region. Sub-Group B 17 to 20 interhaemals and 15 to 18 inter- neurals in caudal region. 3 interhaemals between the first and second anterior caudal spines. Caranx latus 17 interhaemals and 15 or 16 intemeurals in caudal region. Text-figure 2. 1941] Crandall: Description of an Egg of the Long-tailed Bird of Paradise 47 9. Description of an Egg of the Long-tailed Bird of Paradise. Lee S. Crandall. Plate I. On June 16, 1937, a pair of Long-tailed Birds of Paradise, Epimachus meyeri meyeri Finsch, collected by F. Shaw Mayer “near the head of the Waria,” were received at the Zoological Park. During following years, frequent displays of the male were noted but as this is a common practice in the group and there was no evidence of nesting activity, we expected no further re- sult. However, the female was noticed in coma- tose condition on the afternoon of February 28, 1941, and on examination was found to be egg- bound. She responded well to treatment and the egg was safely laid about two hours later. Since the egg of this species appears to be undescribed, the following notes are given. The egg measures 44.25 X 28.5 mm. Its weight was 18.9 grams or approximately .62 ounces. The ground color is buff (close to Cart- ridge Buff of Ridgway). It is heavily blotched and streaked at the large end, the markings decreasing toward the small end, which is almost clear. The under markings are grayish (close to Pale Mouse Gray of Ridgway) while those on the surface are reddish-brown (near Russet of Ridgway) . 48 Zoologica: New York Zoological Society [XXVI: 9 EXPLANATION OF THE PLATE. Plate I. Fig. 1. Egg of Epimachus meyeri meyeri Finsch. Actual size. CRANDALL. PLATE I FIG. 1. DESCRIPTION OF AN EGG OF THE LONG-T A I LED BIRD OF PARADISE 1941] Breder cfc Krumhols: On the Uterine Young of Dasyatis sahinus 49 10. On the Uterine Young of Dasyatis sabinus (Le Sueur) and Dasyatis hastatus (De Kay). C. M. Breder, Jr. & Louis A. Krumholz New York Aquarium and University of Illinois. (Text-figures 1 & 2). The small sting ray, Dasyatis ( Amphotistius ) sabinus (Le Sueur) is abundant along the west coast of Florida in the vicinity of the field station of the New York Aquarium on Palmetto Key. Here mature gravid females may be found at sizes not greatly exceeding those of the relatively new- born young of the much larger Dasyatis hastatus (De Kay). Apparently there is a dearth of material in the literature concerning the size of gravid fe- males, the number of young per individual and the sex ratios of the young. The catches of the stop-netters operating in Bull’s Bay (Cara Pelau on the northern side of Charlotte Harbor on the U. S. coastal charts) provided the data of the accompanying tables, except as noted. The 1939 material was collected by M. B. Bishop of Peabody Museum, Yale University. The sizes of some of the gravid females of D. sabinus did not greatly exceed those of the new-born young of D. hastatus taken on June 29. These latter ranged from 160 to 176 mm. in length, while one not quite mature male of the former was only 174 mm. long. Three full-term embryos taken from one female D. sabinus varied in length from 99 to 100 mm. It can be seen that there is a steady increase in size of the embryos of D. sabinus from a mean of 35.8 mm. on June 19 to a mean of 99.6 on July 11. Also, there was no overlapping of the means and extremes on the various dates. If this can be taken to indicate the growth rate, on so few data, it is remarkably rapid. If the length of the disc (from the tip of the snout to the posterior border of the disc) is com- pared with the width, it is seen that the two dimensions are nearly equal. Moreover, this relationship holds from the smallest embryos obtained through to the adult (Text-fig. 1), clearly showing it to be a straight line relation- ship. D. hastatus, which is a little wider than long, has a similar straight line relationship, but is not so close to a 45° angle. This is clearly a most unusually constant growth rate for which there is no superficial explanation at this time. It is not of importance in intra-uterine life nor can it be in post-uterine life when the extremely different relationships of various other species of rays, otherwise much alike, are taken into con- sideration. The growth relationship of these is so constant that it might be simulated to flap- jack batter spreading out on a pan. Except in the early embryos, this relationship is sufficient to separate these two species which so closely resemble each other. Text-fig. 1 also indicates the relative sizes of the adults and also the size of the young at delivery. A full-term young of each species is illustrated in Text-fig. 2 for purposes of comparison. The general shape and the presence of the keel on the tail of D. hastatus make separation simple. The folding in of the tail, at its origin from the body, in D. hastatus as compared with the flaring out in D. sabinus is another characteristic. It was not always possible to identify each young fish with its mother, because in capture some of the females aborted, resulting in a mix- ture of mothers and young. These young, even though the yolk sac was still hanging outside the body, were able to swim around actively when placed in an aquarium. To avoid possible mistakes and confusion, the young have been considered in groups as taken. The material did show a variation in numbers of young from one to three in D. sabinus and from two to five for D. hastatus. On June 19, 1940, there was one gravid D. sabinus which carried but one embryo. This embryo was nearly twice the size of the others taken on the same date. However, on June 28, 1940, we took another female which carried but one embryo and this was very nearly the same size as others taken on the following day. The sex ratios of all the embryos of D. sabinus combined (25) showed 56% to be male. How- ever, one mother carried three female embryos. 50 Zoologica: New York Zoological Society Table I. [XXVI: 10 Size and Sex of Dasyatis Embryos. Dasyatis sabinus. Disc in mm. Female Male All Date Length Width Sex Max. Mean Min. Max. Mean Min. Mean 4/9/39 55 55 m) Captiva Pass 49 48 f) 49 49 49 55 55 55 52 6/19/40 30 29 f 33 32 f 33 30 f 50 53 f 33 30 m 50 38.5 30 33 33 33 35.8 6/28/40 78 81 m — — ■ — ■ 78 78 78 78 6/29/40 71 72 f 74 77 f 82 81 f 83 87 f 68 69 m 69 67 m 70 71 m 70 73 m 70 74 m 71 72 m 71 * 74 m 74 75 m 75 76 m 77 79 m 79 81 m 79 81 m 83 77.7 71 79 72.9 68 75.2 7/11/40 99 99 f East side of Useppa Island 99 99 f 100 101 f 100 99.6 99 — — — 99.6 Dasyatis hastatus. 4/9/39 76 83 f Captiva Pass 75 83 f 76 75.5 75 75.5 4/10/39 97 102 m Captiva Pass 95 101 f 97 97 97 95 95 95 96 6/24/40 85 87 f 82 88 f 86 87 m 85 89 m 82 82 82 85 85 85 83.5 6/29/40 172 193 f 176 197 f 160 189 m 170 192 in 168 195 m 176 174 172 170 166 160 169.2 The relatively few young of D. hastatus (9) showed 55.5% to be male. Since there were in all 12 gravid D. sabinus and 25 embryos, they averaged 2.08 per mother. The four D. hastatus females averaged 3.25 per mother. These latter are much larger in relation to the size of the young they liberate; the difference in number seems to be purely mechanical. 1941] 51 Date 6/19/40 Length to notch 6/28/40 6/30/40 7/11/40 6/24/40 6/29/40 Unlabeled Breder & Krumholz: On the Uterine Young of Dasyatis sahinus Table II. Size and Sex of Dasyatis Adults. Dasyatis sabinus. Length Width Sex (201 — f not gravid 202 — f not gravid 214 — f not gravid 222 223 f f gravid gravid ■5 embryos 244 — f gravid 247 — • f not gravid 262 — f not gravid 190 — m 190 — m 199 — m 213 — m 218 — m (234 — m 238 245 f gravid 1 embryo 174 179 m imm. — 235 f gravid ■ — 241 f gravid 243 245 f gravid — 254 f gravid 16 embryos — 260 f gravid — 286 f gravid — 286 f gravid 220 224 m — 235 m 291 297 f gravid 3 full term embryos (all females) Dasyatis hastatus. 851 984 f gravid 4 embryos — Circa 914 f gravid 5 embryos 272 310 f not gravid LENGTH OF DISC. MILLIMETERS 52 Zoologica: New York Zoological Society [XXVI: 10 Text-figure 1. Comparison of length and width of disc in pre-natal and post-natal Dasyatis based on data in Tables I and II. 1941] Breder & Krumholz: On the Uterine Young of Dasyatis sabinus 53 Text-figure 2. Dorsal view of full-term embryos of two species of Dasyatis. 1941] Shlaifer: Respiratory Behavior in Small Tarpon 11. Additional Social and Physiological Aspects of Respiratory Behavior in Small Tarpon. Arthur Shlaifer New York Aquarium & U. S. Fish & Wildlife Service, Woods Hole, Mass. Introduction. Tarpon, Tarpon atlanticus (Cuv. & Val.), whose swimbladders contain considerable al- veolar tissue, periodically rise to the surface to breathe atmospheric oxygen despite their ex- tensive gill surfaces and the relatively high oxygen content of the waters they normally inhabit. The work reported here represents a continu- ation of the program of investigation with small tarpon begun by Shlaifer & Breder (1940). In this earlier work, which, incidentally, is the first experimental report on this fish, it was found, among other things, that the surface rise of a tarpon to gulp air may induce similar rises in others in a group. For instance, in a group of four in a 50-liter aquarium, in 70% of the cases a rise by one tarpon would induce a rise in one or more companions. It was shown that “coinci- dence” was not involved as a disturbing factor and that, apparently, a tarpon had to be in a “physiologically receptive” state by virtue of a depleted oxygen supply before such imitative rises could be induced. In preliminary experi- ments, some success was attained in inducing rises by means of a silver-painted carved wooden tarpon model manipulated so as to simulate the normal rise of this fish. In the present report “model” experiments were considerably ex- tended. Shlaifer & Breder (1940) found that while the locomotor activity of tarpon did not change when the oxygen content of the water was raised from 2.50 cc. per liter to 5.60 cc., the rate of surface (respiratory) rises to gulp air decreased markedly. As a continuation of this line of in- vestigation, experiments were performed to de- termine the effect of waters of distinctly low oxygen content on locomotor activity and surface rises; also, survival time was determined for tarpon whose access to the surface and hence to atmospheric oxygen was cut off. The writer wishes to express his appreciation to Dr. C. M. Breder, Jr., of the New York Aquarium for the experimental animals and to the U. S. Fish and Wildlife Service at whose Woods Hole laboratories the experiments were performed. The Induction of Imitative Respiratory Rises. As discussed above, it has been found (Shlaifer & Breder, 1940) that imitative surface rises in small tarpon may be induced by a ma- nipulated wooden model as well as by other tarpon. Models have been used with and with- out success in various lines of investigation on behavior in fishes. Thus, Lissmann (1932) found that the characteristic fighting reaction of the Siamese fighting fish, Betta splendens, is elicited by plasticine models or paintings of the fish. Noble (1934) working with the dwarf sunfish, Eupomotis gibbosus, and Breder (1936) with the sunfish, Lepomis auritus, found that males would attempt to mate with a variety of objects irrespective of their general appearance provided they were manipulated so as to re- semble somewhat the actions of a female ready to spawn. On the other hand, Spooner (1931) found that the bass, Morone labrax, was not attracted by various rough models of itself. Breder & Coates (1935), investigating the sex recognition of the guppy, Lebistcs reticulatus, found that no reaction was given to carefully made models of female Lebistes with or without movement. Finally, Shlaifer (1940) failed to obtain a reaction to sunfish models by goldfishes. Granted that a properly manipulated wooden model may induce imitative rises in tarpon, will other objects properly manipulated but differing appreciably from a tarpon in shape and color also induce rises and if so to what extent? Will a tarpon model or other objects be effective if manipulated so as to rise in a manner appreciably different from the normal one? In an attempt to answer these questions the experiments de- scribed below were performed. Materials and methods. The animals used in these and other experiments described in this paper were 10-12 cm., presumably young, speci- mens sent from the collection at the New York 56 Zoologica: New York Zoological Society Aquarium but originally obtained along the Florida coast. They were kept in sea water and were fed chopped herring three times a week. The experimental group in the model tests was composed of six tarpon placed in 40 liters of standing sea water in a 48-liter rectangular as- sembled aquarium with transparent glass sides, whose dimensions were 55 cm. by 35 cm. and 25 cm. deep. The water temperature range was 19-22 degrees C. and the average oxygen content was 2.50 cc. per liter. Four different types of object, all 10 cm. in length, were used as “models” in the attempts to induce imitative rises in the experimental animals. These were: 1. A silver-painted carved wooden model of a tarpon having no fins or mouth but possessing an “eye” fashioned out of a thumbtack. 2. A white spatula. 3. A piece of red rubber tubing 1 cm. in diameter. 4. A solid glass rod 4 mm. in diameter. Two pieces of string were attached to these objects at opposite ends. The object to be tested was suspended horizontally in the experimental aquarium con- taining the six tarpon, next to the long side of the aquarium nearest the observer, at a distance of 3.5 cm. from the bottom, the level at which the tarpon in that situation generally swam. The observer, seated about two feet away from the aquarium and facing one long side, manipu- lated the object by means of the two strings. The normal air-gulping rise of a tarpon is a rapid movement lasting a little less than a second from the start of the rise to the return to the normal position. Usually the animal rises to the surface almost vertically. In A of Table I this type of rise was simulated by properly manipulating the objects. In B of Table I the object or model was manipulated so as to produce a distinctly “ab- normal” rise. The object was raised to the sur- face parallel with it rather than at a right angle and the rise from beginning to end lasted two seconds. The data in Table I are listed in terms of successful attempts to induce rises in the tarpon by means of the manipulated objects. Each time the object is raised to the surface is considered an “attempt.” The attempt is con- sidered successful if within one second or less following the start of the rise of the model one or more tarpon rise to the surface. Rises by the fishes two or three seconds after the object had risen might also have been imitative delayed reactions but were not considered. Indeed, such rises very rarely occurred. Either the fish would respond immediately or it would not rise for a minute or more. No effort was made to differ- entiate between induced imitative rises that in- volved varying numbers of tarpon. In fact, such differentiation is very difficult if not impossible since, except in rare cases in which two or more individuals arose at exactly the same tune, one cannot determine whether the rise of the tarpon following very closely that of the first animal to rise is a response to the object or to the first tarpon. Observations were made within a ten-minute experimental period. Every second, fourth, [XXVI: 11 sixth, eighth, and tenth minute on the minute the model was raised to the surface and the reaction noted. As a control, every first, third, fifth, seventh, and ninth minute on the minute an observation was made for rises of the tarpon without the manipulation of an object. Each observation, control and experimental, at the two minute interval lasted only one second. In general, observations were made during two con- secutive hours, or 12 experimental periods each day. Results. The data in A of Table I indicate that all four types of objects induce imitative rises whose statistical significance compared with the controls is very high. The average rise of a tarpon in the experimental aquarium was twice in ten minutes. In a group of six animals there would be at most twelve seconds of rising in 10 X 60 or 600 seconds; thus, according to the laws of chance, rises of tarpon directly following those of models cannot very well be considered coinci- dental. It is seen that, of the four objects used, the wooden tarpon model is significantly most ef- fective and the red rubber tubing is second. The degree of success in inducing imitative rises is, however, sharply limited by the physiological state of the animal. As Shlaifer& Breder (1940) demonstrated, a tarpon will not respond imita- tively to the rise of another object, even if it be an- other normal tarpon, unless, by virtue of the fact that the oxygen obtained at the last gulp is dis- tinctly depleted, it is in a “physiologically recep- tive ” state which permits a rising response. The induction of an imitative rise, then, depends on the reaching of a respiratory threshold by the reacting animal. This explains why even the wooden tarpon model enjoys only 48.3% success in inducing rises. The experimental animals may rise either singly or imitatively in groups just before the model is raised to the surface. If so, even raising the object consecutively three times or more will produce no response. The data in B of Table I demonstrate that objects manipulated so as to rise in an “abnor- mal” way induce few i mitative rises . Comparison with the controls indicates no statistical signifi- cance . Surface Rises in Blinded Tarpon. That the induction of imitative rises in small tarpon is a visual affair was demonstrated by Shlaifer & Breder (1940). It was found that the rise of a tarpon on one side of a transparent glass plate bisecting an aquarium could induce a rise in others on the opposite side. Carrying this a step further, four tarpon were blinded by piercing the cornea. Blindness was ascertained by appropriate tests. Several days were allowed for recovery from the operation. Subsequently, the animals were grouped together in 40 liters of standing sea water (oxygen con- tent— 2.50 cc. per liter) in a 48-liter aquarium whose dimensions have been listed above. In the course of several hours of observation no imitative rises occurred. The tarpon rose 57 1941] Shlaifer: Respiratory Behavior in Small Tarpon Table I. The Induction of Imitative Surface Rises in Small Tarpon by Various Objects. A. Object manipulated so as to simulate a normal surface rise. I Silver II Ill IV V Type of Model Wooden White Red Rubber Glass Control2 Tarpon Spatula Tubing Rod Total Number of Attempts1 176 181 176 170 703 Number of Successful Attempts 85 52 62 35 12 % of Successful Attempts 48.3 28.7 35.2 20.6 1.7 1 Object is raised to surface for one second every two minutes in a 10-minute observation period in an attempt to induce a rise in the experimental tarpon in the aquarium. 2 Observation made for one second every two minutes in the 10-minute period for rises by tarpon without manipu- lation of objects. Statistical significances (number of successful attempts).* I vs. II — .0096 I vs. Ill — .0210 I vs. IV — .0013 II vs. Ill — .4370 II vs. IV— .2898 III vs. IV— .0210 I, II, III, IV vs. V— .0000 * Upper limit of statistical significance is set at 0.05. This is three times the probable error. 0.01 indicates good significance while a value of 0.100 or more indicates little significance. (“Student,” 1925.) B. Manipulation of object does not simulate a normal rise.f Type of Model Total Number of Attempts1 Number of Successful Attempts % of Successful Attempts I Silver Wooden Tarpon 65 5 7.7 II III White Red Rubber Spatula Tubing 65 65 5 1 7.7 1.5 t Object is raised to surface slowly and parallel with the surface. 1 See 1 above. 2 See 2 above. Statistical significances (number of successful attempts). I vs. II — None II vs. Ill— .3834 I vs. Ill — .3342 II vs. IV— .4370 I vs. IV — .4954 III vs. IV — .5580 I vs. V— .1832 III vs. V— .5580 IV Glass Rod 65 2 3.1 V Control2 260 6 2.3 II vs. V — .2146 IV vs. V— .5580 I (A) vs. I (B)— .0000 II (A) vs. II (B)— .0000 III (A) vs. Ill (B)— .0000 IV (A) vs. IV (B)— .0000 V (A) vs. V (B) — .4954 individually at the same rate as did the normal animals, once every five minutes. Thus, it is apparent that in the absence of vision no imi- tative rise will occur; possible response to pres- sure stimuli does not obtain. The normal rate and type of surface rises in these blinded forms indicates that this pattern of behavior is not dependent on vision for its proper execution though imitative response by one fish to another is. Locomotok and Respiratory Activity in Waters of Low Oxygen Content. In previous experiments (Shlaifer & Breder, 1940) it was found that when the oxygen content of the water was increased from 2.50 cc. to 5.60 cc. per liter, the rate of respiratory activity (surface rises) decreased significantly though the locomotor activity remained the same. It be- comes desirable, therefore, to determine the respiratory activity and, to a minor extent, the locomotor activity at very low oxygen levels. Small tarpon, incidentally, are relatively hardy forms and are adaptable to a variety of situations. They endure handling in the laboratory remark- ably well and would be excellent laboratory material for many lines of research were they to be found more frequently and in greater abund- ance. They may be found both in the sea and in land-locked pools which are brackish or fresh- water. Some of these pools have relatively little dissolved oxygen but the tarpon survive. Materials and methods. Tarpon were placed in isolation in 7 liters of standing sea water in 8-liter rectangular battery jars whose dimensions were 20.5 cm. by 18 cm. and 21 cm. deep at the 7-liter mark. The water temperature range was 19-22 degrees C. The rates of surface rises and locomotor activity were determined for 15-minute periods. The rate of locomotor activity was determined by an observational technique which is fully described elsewhere (Shlaifer, 1938). Briefly, 3-crn. squares were ruled in red India ink on all four vertical sides of the rectangular battery jar. Using the eye of the tarpon as an anatomical landmark, the number of squares, actually cubes when projected in space, traversed in a 15-minute period was multiplied by 3 to give the results in centimeters. Since this tech- nique is not as accurate as the simple observation of surface rises and since the experimental vessels, considering the size of the tarpon, were quite small and thus limited activity, the rate of surface rises in this set of experiments may be considered the more important feature. Oxygen content was determined by means of the permanganate modification of the Winkler method. Results. Conparing the data in Table II with the results of Shlaifer & Breder (1940), it is seen that at the lower oxygen content the rate 58 [XXVI: 11 Zuologica: New York Zoological Society of respiratory rises increases significantly and the centimeters traversed per rise decreases. The significantly lower rate of locomotor activity at the lower oxygen level may be due primarily to the distinctly smaller vessel in which the tarpon were kept in these experiments rather than to the low oxygen content. As previously mentioned, Shlaifer & Breder (1940) found that while raising the oxygen content from 2.50 to 5.60 cc. per liter in the same aquarium reduced the rate of respiratory rises it did not affect activity. At any rate, the number of surface rises increases at the lower oxygen content de- spite the decreased activity. ously listed. In the first four experiments standing sea water was used; in the fifth, sixth, and seventh, running sea water. In all cases the battery jars were filled to capacity. In the standing water series, a fine wire screen cut so as to insure a tight fit was placed inside the battery jar at the 7-liter mark and in Expts. 5-7 a similarly tight-fitting wooden screen was placed at the same level. In each test the experimental tarpon was allowed a 48-hour period of acclima- tization in the battery jar with access to the surface. At the end of that time the screen was put in place and the time and oxygen content noted. Each battery jar contained only one Table II. The Locomotor Activity and Respiratory Rises of Small Tarpon in Waters of Low Oxygen Content. A. This set of Experiments B. Shlaifer & Breder (1940)3 Mean Oxygen Mean Locomotor Content cc. /liter Activity1 Mean Respira- tory Rises2 Mean cm. per Rise 1.02 304.0 3.6 84.4 2.40 480.0 2.9 165.5 1 Expressed in centimeters traversed per fish per 15-minute period of observation. Figure given is the mean of 80 such periods. 2 Expressed in surface rises per fish per 15-minute period of observation. Figure given is the mean of 80 such periods. 3 Based on Table I (AI), Shlaifer & Breder (1940). Figures given are for an isolated tarpon in 48 liters of sea water in a 50-liter aquarium. Figures for locomotor activity and respiratory rises represent the mean of 48 15-minute observation periods, Statistical Significances (A vs. B) Locomotor Activity: .0003 Respiratery Rises: .007 Finally, it may be noted that if access to the surface is provided, tarpon will survive well in waters of low oxygen content and will utilize relatively more atmospheric oxygen. Survival with No Access to the Surface. The air-breathing habit in tarpon is peculiar in view of the fact that they normally inhabit fairly highly oxygenated sea water and have rather extensive gill surfaces. The value of the air-breathing habit in land-locked pools of low- oxygen content in which tarpon may be found is obvious. However, its persistence in the w-aters of the open sea may possibly be an indication of imperfectly functioning gills, despite their size. It becomes of interest, therefore, to determine the survival time of tarpon when cut off from access to the surface and thus forced to rely on dissolved oxygen. Hora (1933) states that various air-breathing swamp fishes can be “drowned” if prevented from reaching the water surface. Das (1935) states that the air-breathing loach, Lepidocephalus guntea, if prevented from reaching the surface, will be asphyxiated in a little more than an hour. These fishes, however, inhabit waters in which the oxygen content is habitually low in contrast to the tarpon of the open sea. Materials and Methods. In Expts. 1-7 of Table III, the experimental vessels were 8-liter battery jars whose dimensions have been previ- individual at a time. A record was kept of the number of hours between the start of the experi- mental period and the end, which in every case was at the death of the tarpon. Oxygen de- terminations were made each day and at the conclusion of the experiment. The locomotor activity and surface rising of the fish were also noted but only in a general way. As controls, individual tarpon were kept in battery jars in running and standing sea water without being screened from the surface. In Expts. 8-13, the experimental vessel was a 56-liter rectangular assembled aquarium with transparent glass sides whose dimensions w-ere 60 cm. by 35 cm. and 27 cm. deep. This was kept constantly filled to capacity with running sea water. The bottom of the aquarium was covered with sand. Into this aquarium was placed a tight-fitting wire mesh screen containing three squares to the inch, at a level of 6 cm. above the bottom sand. The general procedure followed was the same as that described for the battery jar tests except that no observations were made for activity or surface rises. Results. The data in Table III demonstrate that compelling a tarpon to rely on dissolved oxygen by screening it from the surface will re- sult in asphyxiation in from 7 to 128 hours. Death may occur in a relatively short time even in running sea water (Expt. 5). In the standing water tests the oxygen content at the death of 1941] 59 Shlaifer: Respiratory Behavior in Small Tarpon the animal is high enough to maintain a tarpon indefinitely if it is permitted to respire atmos- pheric oxygen. There seems to be considerable individual variation in survival time. This may be a reflection of individual variations in meta- bolic rate. In the battery jar tests the tarpon would often make desperate and repeated futile attempts to reach the surface and, failing, would sink exhausted to the bottom, there to remain quiescent for long periods of time. In the aquari- um tests, much more area was allowed for normal swimming by the fishes; also, the position of the screen, 6 cm. above the bottom, prevented exhausting and futile attempts to reach the sur- face. Tarpon in this aquarium, even when not screened from the surface, normally swim near the bottom so that the experimental situation in this case is, except for the screen, quite normal. In the control tests, tarpon in battery jars with access to the surface survived indefinitely even when the standing water oxygen content was quite low. Discussion. It is interesting to note in the model experi- ments that imitative rises may be induced by very crude objects differing appreciably in form and color. At the same time, a more finished wooden model is more successful than are the crude ones. The results in B of Table I indicate that movement rather form or color is the im- portant factor for, if the model is so manipulated that the normal rise of a tarpon is not simulated, there is no significant induced imitation, even with the wooden model. Nevertheless, a properly ma- nipulated silver wooden model is more successful than are properly manipulated objects that are distinctly cruder models. Apparently, then, form and/or color may also be involved but only in a minor supplementary way. Possibly at a distance of several inches or more from the re- acting tarpon the type of wooden model used was more visible than were the other objects. Using this imitative rising reaction, it may be Table III. Effect of Prevention of Surface Rises on the Survival of Small Tarpon. Remarks Periods of great activity and attempts to reach surface followed by periods of quiescence. U Tarpon very active — many attempts to reach surface. Tarpon very active. Activity and rises of fish increase markedly one day before death. Experi- ment No. Water Oxygen Content* Survival in Hours I1 Standing 3.39-2.20-1.60 53 21 Standing 3.47-2.98-2.70-2.52 71 31 Standing 4.15-3.20-1.68 51 41 Standing 4.07-1.92 11 5l Running 4.86 7 61 Running 5.58 72 71 Running 5.58 128 8= Running 5.58 32 92 Running 5.58 115 102 Running 5.58 125 ll2 Running 5.58 24 122 Running 5.58 34 132 Running 5.58 46 * In the standing water experiments, the oxygen content represents the oxygen content of the medium at the death of the experimental animal. In the running water series, the figures given represent the average oxygen content in cc. per liter day by day. 1 Experimental vessel is an 8-liter battery jar. 2 Experimental vessel is a 56-liter aquarium. In several cases attempts were made to revive tarpon which, after a long period of time, were near asphyxiation and lay on their sides. They were permitted to come in contact with the surface but evidently were too far gone, for they soon died. In one case, however, three blinded tarpon, which when screened from the surface in standing water in a battery jar soon approached exhaustion and asphyxiation, did recover when the screen was removed after one hour. In that time, unlike normal tarpon, they kept rising al- most continually in attempts to penetrate a screen which they could feel but could not see and within 40 minutes lay on their sides. Das (1935) reports that the air-breathing loach will recover from partial asphyxiation if permitted to rise to the surface after being kept under a screen. possible, by employing a great variety of objects differing in form and color but manipulated normally, to obtain data which may be of sig- nificance in obtaining a measure of the visual acuity of tarpon. The data already obtained, showing as they do only a slight though real difference between a good and a crude model in their relative success at inducing rises, tend to indicate that such experiments would require considerable data to have any significance. It has been seen that preventing a tarpon from utilizing atmospheric oxygen will eventually be fatal, even in highly oxygenated water. Hence, there is no question of the survival value of the surface rise pattern of behavior in these forms. In contrast to the work of Hora (1933) and Das 60 Zoologica: New York Zoological Society (1935), the asphyxiation of tarpon under screens is a very slow process. Undoubtedly there is interesting material here for exhaustive physi- ological studies. It is quite difficult to evaluate the pattern of imitation in surface rising in a group of tarpon. Shlaifer & Breder (1940) have shown that imi- tation will not occur, apparently, until a respira- tory threshold is reached. An isolated tarpon will rise periodically in response to physiological need and over a period of time not much more frequently if it is in a group. It is difficult, at least at this time, to attribute any adaptive value to this imitative behavior which might be termed “social respiratory facilitation.” Summary. 1. Imitative air-gulping surface rises in small [XXVI: 11 tarpon may be induced by relatively crude models if they are manipulated so as to simulate the normal surface rise of this form. A relatively more life-like wooden tarpon model is more successful than are the cruder objects. No signifi- cant success is attained with any model if its ma- nipulated rise differs appreciably from the normal. 2. The imitative pattern is based on visual stimuli rather than on differential pressure stimuli. Blinded tarpon never rise imitatively. 3. At distinctly low oxygen levels, the rate of respiratory rises increases but if access to the surface and hence to atmospheric oxygen is maintained the tarpon survive. 4. Tarpon when prevented from utilizing atmospheric oxygen succumb in 7 to 128 hours even in highly oxygenated running sea water. Literature Cited. Breder, C. M., Jr. 1936. The reproductive habits of the North American sunfishes, Centrarchidae. Zoo- logica, 21: 1-48. Breder, C. M., Jr., & Coates, C. W. 1935. Sex recognition in the guppy, Lebistes reticulatus Peters. Zoologica, 19: 187-207. Das, B. 1935. On ecology and bionomics of an air- breathing loach, Lepidocephalus guntea (Ham. Buch.), with a review on air- breathing fishes. Proc. Xllth Intern. Congr. Zool., Lisbon, 2: 866-920. Hora, S. L. 1933. Respiration in fishes. Jour. Bombay Nat. Hist. Soc., 36: 538-560. Lissmann, H. W. 1932. Die Umwelt des Kampffisches ( Betta splendens Regan). Zeitschr. Vergleich. Physiol., 18: 65-111. Noble, G. K. 1934. Sex recognition in the sunfish, Eupomotis gibbosus (Linn6). Copeia, (4): 151-155. Shlaifer, A. 1938. Studies in mass physiology: effect of numbers upon the oxygen consumption and locomotor activity of Carassius auratus. Physiol. Zool., 11: 408-424. 1940. The locomotor activity of the goldfish, Carassius auratus L., under various con- ditions of homotypic and heterotypic grouping. Ecology, 21: 488-500. Shlaifer, A. & Breder, C. M., Jr. 1940. Social and respiratory behavior of small tarpon. Zoologica, 25 : 493-512. Spooner, G. M. 1931. Some observations on schooling in fish. Jour. Marine Biol. Assoc. United Kingdom, 17: 421-448. 1941] Smith: Notes on Mexican Snakes of the Genus Trimeresurus 61 12. Notes on Mexican Snakes of the Genus Trimeresurus. Hobart M. Smith. A review of the species of Trimeresurus now known from Mexico has revealed some confusion in the literature, to which I personally have contributed to some extent. In addition to correction of some of these errors, the present paper presents two forms new to the fauna of Mexico, names a population previously associ- ated with lansbergii, and diagnoses in a key the eleven forms definitely known to occur in the country. It should be noted that schlegelii, treated by Terron (Anal. Inst. Biol. Mex., vol. 1, 1930, pp. 196-7, fig. 7) as a member of the Mexi- can fauna (without locality), has never been reported nearer Mexico than the “Guatemala” record of Boulenger (Cat. Snakes, vol. 3, 1896, p. 567). Its existence in the country is prob- lematical. I am much indebted to Dr. E. R. Dunn, who has very generously checked the types of brachy- stoma and made a number of valuable additions to the paper. The study has been completed, and a portion of the material on which it is based has been collected, during tenure of a Walter Rathbone Bacon Traveling Scholarship. Trimeresurus godmani (Gunther). Bothreichis godmanni Gunther, Ann. Mag. Nat. Hist., ser. 3, vol. 12, 1863, pp. 364-365, pi. 6, fig. G (Totonicapam, Guatemala). Bothrops godmani Martin del Campo, Anal. Inst. Biol. Mex., vol. 9, 1938, p. 229, fig. 2. One specimen from Santa Rosa, near Comitiin, Chiapas, was reported by Martin del Campo. It has 142 ventrals, 33 caudals, dorsals in 21 rows, 9-10 supralabials. I have examined six specimens, all from Guatemala and Costa Rica. Trimeresurus barbouri (Dunn). Lachesis barbouri Dunn, Proc. Biol. Soc. Wash., vol. 32, 1919, pp. 213-214 (Omilteme, Guerrero) . Published by permission of the Secretary of the Smith- sonian Institution. Agkistrodon browni Shreve, Copeia, 1938, p. 9 (Omilteme, Guerrero). This diminutive species is known only from three specimens collected at the type locality, of which I have examined one, the type of barbouri (U. S. N. M. 46347). I cannot see that browni is different from barbouri. The apparent difference in ventral counts of the types (134, browni; 154, barbouri) is not real, since the browni type is a male, and the barbouri type a female, the ventrals of which should have been written 145 (I count 144 to 147, according to the number of smaller anterior scales counted as ventrals) . The only remaining apparent difference is in the presence of larger head shields, with distinct prefrontals, frontal and parietal in browni. I believe the size of the dorsal head scales varies in this species, as it certainly does in godmani, to which the Omilteme species is related. In six specimens of godmani several intermediate stages between more or less uniform, small scales and the presence of distinct frontals and parietals are shown. Since the type of barbouri has small but distinguishable prefrontals, and since the presence or absence (and size when present) of the frontal and parie- tals is variable in a closely related species, I be- lieve there is no reasonable doubt that browni and barbouri are synonymous. Trimeresurus bicolor (Bocourt). Bothrops bicolor Bocourt, Ann. Sci. Nat., ser. 5, vol. 10, 1868, p. 201 (San Agustin, Guatemala). The only specimen examined is one in the National Museum (No. 46511), from Chicharras, Chiapas. It is a small female with 168 ventrals, 48+ caudals (tail tip missing), 10-11 supralabi- als, 12-12 infralabials, and 10 scales between the narrow supraoculars ; second supralabial enters pit on one side, does not on other. The species is closely related to lateralis Peters (1852), of Costa Rica, which has larger head scales (7 or 8 between supraoculars), a yellow line along outer row of scales and sometimes short black-and-yellow cross-bars (fide Boulen- 62 Zoologica: New York Zoological Society [XXVI: 12 ger). There is no difference between the two in number of labials (the single specimen examined of lateralis has ten), nor in exclusion of the second supralabial from the pit (see above). Trimeresurus nigroviridis aurifer (Salvin). Thamnocenchris aurifer Salvin, Proc. Zool. Soc. London, 1860, p. 459, pi. 32, fig. 1 (Cobdn, Guatemala). Bothrops nigroviridis aurifer a Barbour and Loveridge, Bull. Antiv. Inst., vol. 3, 1929, pp. 1-3; Martin del Campo, Anal. Inst. Biol. Mex., vol. 9, 1938, pp. 228-229, fig. 1. This species was first reported from Mexico by Martin del Campo, who cites a specimen from Santa Rosa, near Comitdn, Chiapas. It has 159 ventrals, 44 caudals (lower than other aurifer reported in the literature), 9-10 supralabials, scales in 19 rows. I have seen no specimens. Trimeresurus atrox (Linnaeus). Coluber atrox Linnaeus, Syst. Nat., 1758, p. 22 (Asia, erroneous). Trimeresurus atrox Schmidt and Andrews, Zool. Ser. Field Mus. Nat. Hist., vol. 20, 1936, p. 182. Specimens of this species have been taken as far north as Valles, San Luis Potosi (Martin del Campo, loc. cit., records it from Tamaulipas) ; it occurs throughout the Atlantic coastal region south of this point, and also along the Pacific coast in southeastern Chiapas. Boulenger records it from farther north on the Pacific coast, from Atoyac, Guerrero (Cat. Snakes, vol. 3, 1896, p. 536). The nineteen Mexican specimens examined differ from South American specimens in the character of the carinae of the median scales, as pointed out by Boulenger (op. cit., pp. 535-539). I can find no other difference. Trimeresurus nummifer nummifer (Ruppell). Alropos nummifer Ruppell, Verz. Senck. Mus., Amph., 1845, p. 21 (Mexico). Trimeresurus nummifer nummifer Dunn, Proc. Biol. Soc. Wash., vol. 52, 1939, pp. 165-166. Specimens are known from central Veracruz along Atlantic slopes into Central America, and on Pacific slopes in southeastern Chiapas. The species is rarer than atrox, and is apparently confined to hilly regions, while atrox is more widespread and ranges from hills to plains. I have examined thirteen Mexican specimens. Trimeresurus nasutus (Bocourt). Bothrops nasutus Bocourt, Ann. Sci. Nat., ser. 5, vol. 10, 1868, p. 202 (Panzos, Rfo Polochic, Guatemala). One specimen (U. S. N. M. 110415) is known from the Mexico-Guatemala border, bearing the locality data Piedras Negras, Guatemala. Dr. E. R. Dunn tells me that there is one in the Museum of the Philadelphia Academy of Natural Sciences, labelled Veracruz (No. 4873, collected by Rev. II. F. Heyde). This is quite different from dunni and yucatanicus, all of which are related; nasutus has a much higher rostral and a different arrangement of the pre- ocular and subocular scales. Two specimens have been examined, the other from Panamd. Trimeresurus dunni Hartweg & Oliver. Trimeresurus dunni Hartweg & Oliver, Occ. Papers Mus. Zool. Univ. Mich., no. 390, 1938, pp. 6-7, pi. 1 (Tehuantepec, Oaxaca). Known from the semi-arid Pacific slopes of the Isthmus of Tehuantepec (seventeen specimens examined). The definition of this species by Hartweg & Oliver has greatly clarified the situation with respect to lansbergii, with which the Tehuantepec as well as Yucatdn specimens were previously associated. Prior to their action, three separate populations of lansbergii were apparent: one in northern South America and in Panamd; one in Oaxaca; and the third in Yucatan. Between Mexico and Panama no specimens related to lansbergii are known. All of this group from that intermediate area are referable either to ophryo- megas or to nasutus (c. f. Amaral, Bull. Antiv. Inst., vol. 3, 1929, pp. 19-27). 1 The isolated group in Yucatan is not the same as dunni, nor can it be referred to typical lans- bergii of South America. I propose the name Trimeresurus yucatanicus sp. nov. Ilolotype. U. S. National Museum 46571, fe- male, from Chichen Itza, Yucatan, collected by Nelson & Goldman, February, 1901. Paratypes. Field Museum of Natural History No. 504, Yucatan, and No. 20621, Chichen Itza, Yucatdn. Diagnosis. Snout turned up in front; rostral no more than one and one-half times as high as wide; scale rows 21 posteriorly; two lower pre- oculars subequal, both excluded from orbit; two large scutes on top of head bordering internasals and canthals, nearly meeting medially; loreal square; caudals 32 to 41 in females; bands on body single. Description of Holotype. Rostral very high, its length (2.6 mm.) somewhat greater than greatest width (2.2 mm.), twice width of upper part (1.3 mm.); internasals elongate, elevated, in con- tact medially; one canthal; preocular encroach- ing on dorsal surface between canthal and supra- ocular; five or six scales between supraoculars; dorsal head scales keeled ; a large scale, as large as canthal, bordering internasal medially, in contact with canthal, separated from its mate by one scale; ten supralabials; first labial in contact with anterior section of nasal, separated from posterior section by a very small scale and a small, wedge- 1 Trimeresurus lansbergii annectens Schmidt is certainly referable to ophryomegas, of which it may be a subspecies. 1941] Smith: Notes on Mexican Snakes of the Genus Trimeresurus 63 shaped protrusion from anterior section; scale between second labial and posterior section of nasal quite small; one row of small scales between labials and border of pit ; two tiny scales between nasal and border of pit; loreal moderately large, nearly square; one moderately large scale be- tween lower preocular and third labial; one row of scales between subocular and labials ; subocular single, very elongate; one very large upper pre- ocular, about twice as large as loreal, somewhat smaller than canthal ; two lower preoculars, both separated from labial border, both small; median preocular partially fused with an elongate scale bordering edge of pit; edge of supraocular thin; edge of canthal somewhat raised, rather sharp anteriorly; edge of preocular not keeled, rounded. Eleven or twelve infralabials; first infralabials in contact with each other behind mental; three labials in contact with chinshields; one large anterior pair of chinshields, about as long as combined width; this followed by two small pairs of scales. Dorsals in 27-27-21 rows; 148 ventrals; 32 caudals, entire; anal entire. Total length 254 mm.; tail 26 mm. Specimen badly faded. Ground color light gray, stippled; seventeen somewhat staggered, darker cross bands, split on middorsal line; blotches covering about six scale lengths, sepa- rated by light areas covering about four scale lengths; anterior and posterior edges of cross bands black, narrowly light-edged ; some blotches faintly divided by a very slightly lighter, trans- verse area; the dark borders terminating about four scale rows lateral to vertebral row ; blotches faintly interrupted at this point, below which are two rounded spots of same color as blotches, separated from each other, and more or less fused with the blotches; belly heavily stippled; a few light marks in labial region. Remarks. So far as now known, the only speci- mens of Trimeresurus from areas north of Panama having a rostral similar to that of lansbergii are those from the Tehuantepec area which have been described by Hartweg & Oliver as dunni, and the present three specimens from YucaUin. The latter three are not the same as dunni, since the bands are not paired; the scale rows usually more numerous in front of anus (21 at anus in one out of 27 dunni, 21 in all three yucatanicus) ; two lower preoculars small, sub- equal, excluded from orbit (middle larger, entering orbit in dunni). From lansbergii itself the present species ap- parently differs in having 21 scale rows posteri- orly, usually more numerous subcaudals (28 to 33 in females, 31 to 36 in males of lansbergii; 32 to 41 in females of yucatanicus)-, two relatively large scutes bordering internasals and canthals, nearly meeting each other medially (no such scales in lansbergii, apparently); loreal square (usually narrow, about twice as long as broad in lansbergii). In 1859 Cope described a form called brachy- stoma ( Proc . Acad. Nat. Sci. Phila., 1859, p. 339). The series on which this name was based is now in the collections of the Philadelphia Academy of Natural Sciences, and consists of four specimens (of which No. 7043 is the type), all collected by Mr. Cuming at unknown localities. All four have 19 scale rows posteriorly, elongate loreals and bands single, and accordingly agree with the characters of lansbergii. They probably were secured in South America, as Dr. Dunn states that numerous other specimens collected by Cuming are in the Academy collections, all apparently from South America. Trimeresurus undulatus (Jan). Trigonocephalus ( Atropos ) undulatus Jan, Rev. Mag. Zool., 1859, p. 157 (Mexico). Specimens in the National Museum are from Orizaba, Veracruz (No. 6319); Omilteme, Guer- rero (Nos. 46345-6, 46348) ; and Oaxaca, Oaxaca (No. 46466). The species has also been reported from the state of Hidalgo (Martin del Campo, op. cit., p. 14). Trimeresurus tnelanurus Muller. Trimeresurus melanurus Muller, Mitt. Zool. Mus. Berlin, vol. 11, pt. 1, 1923, pp. 92-93 (Mexico). Trimeresurus garciai Smith, Proc. Biol. Soc. Wash., vol. 53, 1940, pp. 62-64, fig. 2 (Cacaloa- pam, Puebla). This species is known only from the desert region about Tehuacan, Puebla. Its divided caudals and the horn-like supraocular distin- guish it from all other species in Mexico. Three specimens have been examined. Ivet to Mexican Trimeresurus 1. Supraocular produced as a soft, horn-like scute 2 Supraocular flat 3 2. Subcaudals entire melanurus Subcaudals divided undulatus 3. Snout produced, turned up 4 Snout not noticeably turned up 6 4. Rostral about twice as high as wide. . . .nasutus Rostral no more than one and one-half times as high as wide 5 5. Bands on body distinctly paired; two lower preoculars small, subequal, excluded from border of orbit; scale rows 21 in front of anus yucatanicus Bands on body paired, each half well defined and usually separated medially from its mate; middle preocular considerably larger than lower, broadly in contact with border of orbit; scale rows usually 19 in front of anus dunni 6. Subcaudals double atrox Subcaudals single 7 7. Scales in 23 rows or more; size large nummifer nummifer Scales in 21 rows or less; size smaller 8 8. Width of a supraocular about half distance between supraoculars; subcaudals 22 to 34; brown; terrestrial 9 Width of a supraocular one third distance between supraoculars, or less; subcaudals 44 to 67; green; arboreal 10 64 Zoologica: New York Zoological Society 9. Scales in 21 rows; upper preocular large, forming part of canthal ridge; loreal small, excluded from canthal ridge, not in contact with supraocular godmani Scales in 19 or 17 rows; upper preocular small, excluded from canthal ridge; loreal large, forming part of with supraocular. 10. Head scales smooth; Head scales keeled; [XXVI: 12 canthal ridge, in contact barbouri ; scales in 19 rows nigrovirulis aurifer scales in 21 rows . . tricolor ZOOLOGIGA SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY VOLUME XXVI Part 2 Numbers 13-18 PUBLISHED BY THE SOCIETY THE ZOOLOGICAL PARK, NEW YORK September 8, 1941 CONTENTS PAGE 13. The Life History and Bionomics of the Trematode, Zygocotyle lunata (Paramphistomidae). By Charles H. Willey. (Plates I-IV) 65 14. Eastern Pacific Expeditions of the New York Zoological Society. XXIV. Fishes from the Tropical Eastern Pacific. [From Cedros Island, Lower California, South to the Galapagos Islands and Northern Peru.] Part 1. Lancelets and Hag-fishes. By William Beebe & John Tee-Van. (Text-figures 1 & 2) . . 89 15. Eastern Pacific Expeditions of the New York Zoological Society. XXV. Fishes from the Tropical Eastern Pacific. [From Cedros Island, Lower California, South to the Galapagos Islands and Northern Peru.] Part 2. Sharks. By William Beebe & John Tee-Van. (Plates I & II; Text-figures 1-34) 93 16. Correlations Between Structural Eye Defects and Behavior in the Mexican Blind Characin. By Charles M. Breder, Jr., & Edward B. Gresser. (Plates I-IV ; Text-figures 1 & 2) 123 17. On the Species of Otus scops. By Jean Delacour 133 18. A New Genus of Kaleege Pheasants. By Marquess Hachisuka. 143 1941] Willey: The Life History and Bionomics of Zygocotyle luiiata 65 13. The Life History and Bionomics of the Trematode, Zygocotyle lunata (Paramphistomidae). Charles H. Willey Department of Biology, University College of Arts and Pure Science, New York University (Plates I-IV). Zygocotyle lunata belongs in the family Param- phistomidae Fischoeder, 1901. Diesing (1836) described the species from material collected by Natterer, in Brazil, from the ceca of several species of water birds and from the cecum of the deer, Cervus dichotomus, and named it Amphi- stoma lunatum. Fischoeder (1903) redescribed the species from 4 whole mounts of Diesing’s original material in the Vienna Museum. Stunkard (1917) erected the genus Zygocotyle, to contain A. lunatum and a new species, Z. ceratosa, described by him from the intestine of a duck, Anas platy- rhynchos, from Nebraska. Price (1928) showed that Z. ceratosa was specifically identical with Z. lunata. The host relationships of the genus Zygocotyle are of considerable interest. Diesing (1836) de- scribed it from the cecum of a deer, Cervus dichotomus, and also from the ceca of the birds, Anas melanotus, A. epecutiri and Himantopus wilsonii. Fischoeder (1903), after an examina- tion of 4 of Diesing’s specimens, concluded that the record of the ruminant Cervus dichotomus as a host of this form was probably due to an error in labelling. As pointed out by Price (1928), Dujardin (1845) and Diesing (i850) had earlier arrived at the same conclusion because of the wide difference in hosts. The suspicion of error persisted until the occurrence of Zygocotyle in both birds and mammals was definitely shown by Price (1928) who studied specimens of an amphi- stome reported by Hall (1927) from the cecum of a cow, Bos taurus, and identified them as Zygoco- tyle lunata, thus confirming and validating Diesing’s original record. In the present study, infections with Z. lunata have been experimen- tally produced in the sheep, Ovis aries, and in the rat, Mus norvegicus, as well as in ducks. Thus a rodent as well as another ruminant is here added to the list of mammalian hosts. Ml the rats exposed '(more than 60) became infected. Several years ago the writer (1930, 1936) described a new species of cercaria, C. poconensis, from Helisoma antrosum collected near Henry- ville, Pennsylvania. Life history studies with the material in an attempt to identify the adult stage failed, and the investigation had to be abandoned because the infestation was no longer present in the snails from that region. In Septem- ber, 1937, one specimen of Helisoma antrosum from Prospect Park Lake in New York showed an infestation with Cercaria poconensis, and subse- quent collection of 450 snails from the same lake during October yielded 3 additional infections. Cercariae from these 4 naturally infested snails encysted in dishes in the laboratory and furn- ished the material for feeding experiments. Metacercariae fed to rats, ducks and sheep devel- oped into adults of Zygocotyle lunata in the ceca of these hosts. Eggs, collected from feces, developed in the laboratory and young labora- tory-raised snails of the species Helisoma antro- sum, on exposure to the hatched miracidia, be- came infected, yielding the sporocyst, redial and cercarial stages, thus demonstrating experimen- tally the complete life cycle. Preliminary reports were presented in abstract form (Willey, 1937, 1938). Gower (1938) in a study of trematodes infesting wild ducks in Michigan obtained an experimental infestation in a half-grown mallard duck of 46 immature specimens of Zygocotyle lunata with metacercariae from a naturally infected snail identified as Helisoma trivolvis. Much progress has been made in recent years in the demonstration of North American trema- tode life cycles. Most of the advances have been made, however, in groups other than the amphi- stomes. Life cycle studies in this group, with the exception of that of Bennett (1936) on Cotylo- phoron cotylophorum, are mostly incomplete, since they lack one or more stages or fail to pro- vide experimental proof in support of conclusions based on morphological similarity. The demonstration of a complete life cycle requires that all stages be described and obtained experimentally. The studies may begin with any step in the sequence. In trematode studies either of two modes of attack are commonly em- ployed. One may start with the cercarial stage, 66 Zoologica: New York Zoological Society [XXVI: 13 obtained from naturally infected snails, and expose various possible hosts to it or to the metacercaria, if the cercaria encysts in the open. Such experimental hosts must be known to be free from previous infection which might be confused with the experimental one. Frequently, the structure and activities of the cercariae to- gether with information on the fauna occurring in the same environment will give some indication of the next host. Similarly, one might start with the adult stage of the trematode in the final host. Eggs are then collected and permitted to develop and various species of snails are then exposed to the hatched miracidia. Successful infestation provides the asexual stages in the snail. In either method, the cycle is followed back to the starting point. In the present study the investigation began with 4 naturally infected snails and, as described later, infection was obtained in the final hosts. The rats, all of which became infected, had been laboratory-raised for many generations and the ducks were known to be previously uninfected, because none in a control series of ducks, being used for other experiments, ever showed any eggs or specimens of Zygocotyle lunata, while all the experimentally-fed ducks became infected with the species. The complete life cycle was passed through several times in the laboratory. No further collections of naturally infected snails were made since ample material was available in the laboratory throughout the investigation. The life cycle as here presented begins with a descrip- tion of the eggs obtained from experimentally infected hosts, after which the succeeding generations are considered in the order of their occurrence. The materials and methods em- ployed with the various stages are described separately for each stage. Egg. The eggs of Zygocotyle limata examined alive from feces or from living unstained worms are colorless. The shell is very delicate and as studied in optical sections under high magnifica- tion, it does not exceed 1.5 p in thickness. If pushed about with a blunt needle the eggs are easily dented and burst readily with rough handling (Fig. 1). They are broadly ovoid and show little variation in shape (Fig. 2). The slightly attenuated end bears an operculum measuring from 28 p to 31 p in diameter. The edges of the operculum are irregularly notched and these notches interdigitate closely with similar irregular notches on the edge of the shell. A slight excrescence, from 10 to 15 p in diameter, occurs on the shells of all the eggs at the broad end. The freshly deposited egg contains a large number of granular yolk masses suspended in a transparent fluid; and the ovum, measuring from 20 m to 25 m in diameter, still unsegmented, lies embedded between the vitelline masses in the opercular half of the egg (Fig. 1). Eggs of Z. lunata vary much in size. Several hundred eggs collected from feces of ducks and rats infected with newly matured worms, as well as eggs from infestations of more than a year’s duration, were measured. Eggs from feces of a duck and of a rat, each of which had been infested from a single feeding of metacercariae 13 months previously, show no significant difference in size. The eggs from the duck varied in length from 132 p to 152 n and those from the rat from 132 p to 158 p. Width varied in eggs of the duck para- sites from 92 p to 102 p and in those from the rat from 89 p to 102 p. The average size of 38 eggs deposited by worms in the duck was 142 p by 98 p, while that of the 38 eggs from the rat feces measured 141 p by 96 p. The variation in size of eggs from these 13-mont.h-old worms was 26 p in length and 13 p in width. Bennett (1936) showed a similar size range (30 p in length and 10 p in width) in eggs of Cotrjlophoron cotylo- phorum. Fifty-six eggs of young, newly mature Z. lunata collected in a fecal sample from a duck experimentally infected 48 days before, varied in length from 132 p to 152 p and in width from 99 p to 102 p, the average measurements for the group being 145 p by 99.5 p. Similarly, 54 eggs of young, newly mature worms collected in a fecal sample from a rat infected 49 days before, varied in length from 132 p to 158 p and in width from 92 p to 105 p, the average measurements for this group being 141 p by 98.8 p. As with eggs from older infestations, no significant difference in size ap- pears between eggs of worms in the 2 hosts. Further, it may be seen that the size range is the same for eggs from new and old infestations. While in the eggs measured in these series, the average length and width of eggs from young infestations slightly exceed those of older infesta- tions, the difference is not significant. Thirty eggs measured in stained whole mounts of newly matured worms varied from 132 by 86 p to 152 by 99 p, the average being 143 by 91 p. While the average width (91 p) of these eggs in stained and mounted young specimens is about 5 p less than that of living eggs from older worms, the extremes in both dimensions are practically the same in eggs from fixed and stained specimens of all ages as in eggs from feces. The average obtained for all eggs of Z. lunata measured in the present investigation is 142 p in length and 96 p in width. Price (1928) tabulated measurements of Z. lunata from different hosts and showed a re- markably wide variation in egg size. The eggs measured by Price and others from 7 host species vary from 124 to 153 p in length and from 72 to 96 p in width, the extreme range of variation being 29 p in length and 24 p in width. This range is somewhat wider than in the present study. All of the material used by the present author for egg measurements was obtained from experimental infestations with metacercariae from 2 naturally infected snails collected from the same small pond. The hosts yielding the specimens of Z. lunata for egg measurements as tabulated by Price were natural infections studied under different conditions by different workers and collected from widely separated parts of 1941] Willey: The Life History and Bionomics of Zygocotyle lunata 67 North and South America. The differences in egg size may possibly be explained by this difference in source of material. With regard to egg size in amphistomes, it is difficult to draw any conclusion of value other than that egg size is of little importance in classification within a family. Miracidium. Development. Studies on development of the miracidium of Zygocotyle lunata were carried out on eggs obtained from feces of experimentally infected ducks and rats. All eggs observed were in the one-cell stage at the time of deposition. Much difficulty, due to bacteria and molds, was experienced in obtaining successful development of the ovum. The best results were obtained by keeping the eggs in petri dishes and changing the water twice daily. Immediately after collection from feces, the eggs were washed through 8 or 10 changes of tap water. Other methods involving (1) the use of sterile water, (2) gentle mechanical agitation and (3) a method by which drops of water fell continuously into dishes of water containing eggs were all found to be unsatis- factory. Eggs allowed to develop at a constant temperature of 25° C. in an incubator gave some- what better results than those exposed to varying temperatures in the laboratory. By transferring the eggs twice daily with a micropipette to dishes of clean water, about 50 to 60 per cent of the embryos hatched and even then it was necessary to clean the mold from some of them with dissecting needles before they would hatch. In no case was it possible to obtain complete development without some mold forming on the eggs. Bennett (1936) described in considerable detail the developmental stages of the miracidia of Cotylophoron cotylophorum and found a re- markable similarity in the sequence of organ development between that species and develop- ment in other species of trematodes as described by Thomas (1883), Looss (1892, 1896), Ortmann (1908), Johnson (1920), Stunkard (1923), Barlow (1925), Ishii (1934) and Suzuki (1931). Bennett (1936) says, “The development of the miracidium as described here coincides in practically every detail with the development of the miracidia described by the workers mentioned earlier in this discussion. This result points to the con- clusion that the chronological sequence of organ development in trematode miracidia is essentially the same.” In view of Bennett’s complete account of development in C. cotylophorum, a closely related amphistome, and the similarity manifested in the developmental history of miracidia in trema- todes generally, detailed observations on the sequence of organ development are not recorded here for Zygocotyle lunata. However, all stages were observed in the course of the present study, using living material in hanging drops, and the process in Z. lunata follows very closely that described for C. cotylophorum. The time required for development and hatch- ing varies, the minimum time being 19 days and the maximum 40 days in the material of Z. lunata studied under laboratory conditions. Between these extremes the rate of development varied with the season of the year, more time being required during the colder than in the warmer months. Most of the eggs were embryo- nated at room temperature, and during the winter the room was much cooler during both day and night than in the summer. Temperature is probably the factor controlling speed of devel- opment, but controlled experiments using differ- ent temperatures at the same season of the year were not conducted. Table 1 shows the relation between time required for development and season of the year. In each case the time noted is that time elapsed from deposition of the eggs until emergence of the first miracidium in the given batch of eggs. In all the cultures, hatching was spread out over periods of 4 days or longer, indicating individual differences either in ma- turity of the eggs at deposition or in develop- mental rate. In a culture of developing miricidia of Z. lunata, most of the embryos are at about the same stage of organ formation but some develop more slowly than others in the same dish. Table 1. Seasonal variation in developmental rate of miracidia of Zygocotyle lunata. Date of deposition Date of hatching Days of eggs of first miracidia elapsed Dec. 2, 1937 Jan. 10, 1938 39 Dec. 4, 1937 Jan. 13, 1938 40 Dec. 16, 1937 Jan. 18, 1938 33 Jan. 22, 1938 Feb. 16, 1938 25 Feb. 2, 1938 Feb. 27, 1938 25 Feb. 23, 1938 March 21, 1938 26 March 5, 1938 March 27, 1938 22 March 14, 1938 April 7, 1938 24 April 15, 1938 May 8, 1938 23 May 25, 1938 June 15, 1938 21 June 9, 1938 June 30, 1938 21 June 10, 1939 June 29, 1939 19 July 22, 1939 Aug. 11, 1939 20 July 25, 1939 Aug. 16, 1939 22 Aug. 12, 1938 Aug. 31, 1938 19 Sept. 1, 1938 Sept. 22, 1938 21 Sept. 4, 1939 Oct. 4, 1939 30 Oct. 15, 1938 Nov. 9, 1938 25 Oct. 29, 1938 Dec. 1, 1938 33 Nov. 19, 1938 Dec. 19, 1938 30 Figures 3, 4 and 5 are photomicrographs of embryos of Z. lunata at 13, 18 and 21 days of development respectively, from a culture in which the first miracidium hatched in 21 days. In the 13-day stage the embryo is 135m to 140m long and is slipper-shaped, occupying the entire length of the egg. The yolk masses have begun to increase in size and decrease in number by a process which suggests a coalescence of the con- tents of adjacent masses. Very little movement of the embryo could be observed at this stage. Cilia are present but were not seen to move. The anlage of the “gut” is well established and flame cells are only occasionally seen. They have large nuclei at the base of a small tuft of cilia which measures approximately 6m X 3m. The 68 [XXVI: 13 Zoologica: New York Zoological Society nuclei are visible only after the embryonated egg is somewhat compressed and only after the em- bryo reaches a moribund state. No vitelline membrane could be discerned and from this stage on, the embryo occupies the entire length of the egg. No space is left at either end and the granular mass called a “mucoid plug” by Barlow (1925) and described in detail by Bennett (1936) for Cotylophoron cotylophorum, is entirely absent at all stages in eggs of Zygocotyle lunata. In Z. lunata numerous refractive, spherical masses are usually to be seen lying outside the embryo (Figs. 3, 4). They are left behind when the miracidium hatches and may be excretory in nature. An 18-day old embryo (Fig. 4) shows practi- cally all the body organs well developed and exhibits much movement, shifting backward and forward and constricting the body transversely at the junctions of the rows of epidermal cells. The yolk masses are now few in number and very large. Increase in length and width has necessi- tated a folding forward of the posterior fourth of the body, which becomes J-shaped. The nerve mass is well developed as a concentrated, some- what spindle-shaped band of small cells near the posterior limit of the anterior third of the embryo. The cilia are active, beating spasmodically every few minutes. The flame cells are large (12 n by 5.5 n) and actively beating, but no collecting tubules were observed at this stage. Germ cells are well-defined in the posterior third of the body. The embryo of 21 days development shown in Fig. 5 would not be ready to hatch before 24 to 48 hours although some others in the same culture dish were hatching. Several yolk masses are still present and appear to be partitioning off the part of the egg not occupied by the embryo. These apparent divisions always disappear com- pletely before hatching occurs. At this stage there is much constricting of the body as a whole and of the “ gut ” which is half as long as the body. Granules suspended in a fluid in the “gut” shift back and forth due to apparent waves of con- traction in the wall of the “gut” (Fig. 5). The cilia beat slowly from time to time. Anteriorly, the apical papilla presses closely against the operculum. The embryo maintains a J-shaped form and the position shown in Fig. 5 until the time of hatching. Hatching. With the disappearance of all the yolk masses the content of the egg is a continuous fluid in which the miracidium lies free. It shifts back and forth rapidly and the cilia begin to beat violently. One gets the impression at first that the apical papilla batters against the oper- culum to open it by mechanical pressure. More gentle movements of the same nature take place during the last 2 days before hatching. In the majority of cases the miracidium emerges without having turned around in the egg and this appears to be the normal procedure. Shortly before hatching, many large refractive granules from 4 m to 10 m in diameter, and clusters of smaller spherules, remain more or less stationary within the egg shell, but when the miracidium is ready to emerge, the violent ciliary action causes the granules to be swirled rapidly about with the fluid. Normally the operculum opens within one hour after this violent activity starts and emer- gence of the larva requires from a few seconds to fifteen minutes. Those which require the longer time to get out of the egg shell are apparently abnormal in some way or are injured in emerging, since they usually do not swim far and soon die. The diameter of the operculum is only about half the width of the miracidium which must constrict appreciably as it passes through. During the entire process of emergence the cilia are beating very rapidly. Some miracidia turn around again and again in the shell at hatching time. In such eggs, opening of the operculum appears to be delayed. Some of these larvae emerge normally when the operculum does finally open, but in other eggs the operculum opens only after the miracidium has exhausted itself by its activity and may emerge only half way and die in that position. Some swim around incessantly within the egg shell for as long as 7 hours and die there. It seems significant that in many cases where the larva fails to emerge readily, it turns about actively in the egg and applies the apical papilla against the two ends of the shell with equal fre- quency, apparently trying to find an opening at first one end and then the other. In two such eggs observed in hanging drops, the operculum opened while the apical papilla was directed to- ward the opposite end of the egg. Within a few seconds the larva turned and emerged rather slowly through the opening but swam away vigorously when free from the shell. This obser- vation seems to indicate that glandular secretions are produced at hatching time which effect the opening of the operculum, and that mechanical pressure by the apical papilla is probably not the direct cause for its removal. Normal larvae develop in a position adapted to straight-forward emergence. No embryos were observed develop- ing in a reversed position. A remarkable periodicity exists in the time of day that miracidia of Z. lunata hatch. In ob- servations on hundreds of mature miracidia in many different culture dishes at all hours of the day and night, very few were observed to hatch or to have hatched before 5:00 P.M. and no miracidia were ever found swimming in the cul- tures in the morning after 9:00 A.M. The ma- jority hatched between 10:00 P.M. and 2:0Q A.M. In many cases, mature miracidia were observed in eggs until about midnight or later in order to study the hatching procedure. Often none would hatch, but almost invariably some of them would be found either moving very feebly or dead in the dish at 9 :00 in the morning, having hatched during the early morning hours. Those which had not hatched during the night usually remained in the egg shell until the fol- lowing night, when more would emerge. Darkness does not seem to be the controlling factor, for just as many larvae hatch in a culture dish placed under the strong beam of a microscope 1941] Willey: The Life History and Bionomics of Zygocotyle lunata 69 lamp as in dishes covered with black paper. Attempts to induce consistent hatching of mi- racidia for study during the day, by the stimuli of light and darkness, were entirely unsuccessful. Agitation with dissecting needles of eggs con- taining mature miracidia sometimes causes the operculum to open, probably by mechanical in- jury to the egg shell, but most if not all individu- als induced to emerge in this fashion are abnormal and die without getting very far away from the opened shell. The miracidium swims very rapidly, usually in straight lines for considerable distances before darting off suddenly in a new direction. In Syracuse watch glasses they may be seen either swimming back and forth across the dish or fol- lowing around the edge in either direction. When no snail is in the dish the movements of the larva seem to be entirely at random. No phototropism was observed and they do not show any tendency to concentrate in any one place or in any way to influence each other. They swim incessantly for varying periods up to 7 hours, after which they slow down, sometimes swimming for a time in narrow circles, and die on the bottom of the dish in a somewhat bloated condition and contracted in length. As described in a later section of the present paper, they usually enter the snail host within two hours. Morphology of the Mature Miracidium. Studies on the morphology of mature miracidia of Zygocotyle lunata were conducted, using un- stained living and moribund individuals in hang- ing drops, silver impregnated specimens prepared according to the method described by Lynch (1933), and specimens stained intra vitally with neutral red. When swimming, the miracidium is elongated with sides almost parallel. Anterior- ly it is cone-shaped and terminates in a pro- trusible cap called by some authors the apical papilla. The posterior end is bluntly rounded. Moribund specimens and those which may be momentarily quiescent contract appreciably in length and become broader. The anterior, coni- form region and apical papilla may be retracted and the specimen becomes much expanded in the anterior half. Some variation occurs in size of miracidia of Z. lunata as in other species, but most of it is due to the varying amounts of con- traction and swelling which occur on natural death or fixation. Ten specimens killed by hot 0.5 per cent, silver nitrate for the silver impreg- nation method showed proportions most closely approaching those of the living miracidium. In these 10 specimens length varied from 184 n to 211 /z and width varied from 53 n to 59 n, the average length and width being 194 n and 55 n respectively (Figs. 7, 8) . Ten moribund specimens in hanging drops varied from 170 n to 231 n in length and from 68 n to 75 u in width, the average measurements of this group being 187 n by 69 n- The entire surface except the apical papilla and the very narrow spaces between rows of epithelial cells is ciliated. The cilia (Fig. 6) are about 10 n long except immediately behind the apical papilla where they are about 3 or 4 n long. These short cilia beat as do all the others. The cuticular non-ciliated cap or apical papilla is about 10 n across and a slight constriction of the body wall occurs just behind it. The apical papilla, called by various authors a “rostrum,” “oral cone,” “head papilla,” or a “terebrato- rium,” is said by some to be perforated by small glandular pores. Lynch (1933) described such pores in the apical papilla of Heronimus chelydrae. Coe (1896) found an opening which he refers to as the mouth in the “Ivopfpapille” of the mira- cidium of Fasciola hepaiica. No pores were identified on this structure in Z. lunata, and such pores have not been reported on the papillae of other amphistome miracidia. The external layer of the miracidium of Z. lunata is an epithelium consisting of 20 flattened, ciliated, epidermal cells. They are arranged in 4 tiers or rows, with 6 cells in the first (anterior) row, 8 in the second, 4 in the third and 2 in the last or posterior tier (Figs. 7, 8). These cells are well demonstrated by the silver impregnation technique used by Lynch (1933). Figure 7 is a photomicrograph of a silver impregnated mira- cidium taken with a 16 mm. objective to obtain sufficient depth of focus to show the entire thickness of the specimen. Figure 8 is a photo- micrograph of the same miracidium as in Fig. 7 but using an 8 mm. objective focussed on the upper surface, with consequent loss of depth of focus. The epidermal cells of the first tier covering the anterior fifth of the larval body are triangular in shape due to the tapering at the front end of the miracidium. They converge, almost meet, and seem to unite to form a ring in the base of the apical papilla. The cells of the second and third tiers are rectangular in surface view. Each of the 2 cells in the posterior tier covers one-half of the surface in the posterior fifth of the miracidium, the contiguous borders of the 2 cells lying some- what to the left and right of the median plane. The spaces between adjoining epidermal cells and between tiers of cells in Z. lunata are from 0.5 n to 1.5 n in width as seen in silver preparations. The spaces are homogeneous in appearance, without perforations and are bordered by wavy, irregular lines. No overlapping of plates was observed. Papillae and excretory pores open laterally through spaces between epidermal cells, as will be described later. The disposition of the epidermal plates with regard to the dorso-ventral axis of the miracidium is shown in Fig. 9, which is a dorsal view. Ad- joining borders of the dorsal (and ventral) epidermal cells of the second and third rows lie in the median plane, while those of the posterior row lie in a plane about 45 degrees removed from the median plane. The borders of the 6 anterior cells do not fall in line with any of those of the second row of 8 cells, and the medial edges of the 2 dorsal epidermal cells in the anterior row lie just a little to one side of the median plane. The miracidium shown in the photomicrographs (Figs. 7, 8) lies in a position of about 45 degrees 70 Zoologica: New York Zoological Society [XXVI: 13 of rotation to the right from a dorsal aspect, permitting favorable illustration of the lateral location of excretory pores and lateral papillae. Epidermal cells have been studied in miracidia of a few other species. A review of this work was presented in tabular form by Bennett (1936). The cell formula, 6;8;4;2 was reported by Bennett (1936) for Cotylophoron cotylophorum, and by Krull & Price (1932) for Diplodiscus temperatus. The present work shows that the miracidium of Zygocotyle lunata also possesses the formula 6;8;4;2, indicating that this formula is probably characteristic for the family Paramphistomidae. In studies on these cells in miracidia from other families, Thomas (1883), Ameel (1934) and Lynch (1933) reported some variation between different individuals within a species. In the majority of species, however, in which the formula has been described, no variation is re- ported. In the present work, 25 silver impregna- tion preparations of miracidia of Z. lunata showed no variation in the formula for the epi- dermal plates. As pointed out by Price (1931) and Bennett (1936) these structures are probably of importance in establishing natural relation- ships among the trematodes. Each epidermal cell contains a nucleus which may sometimes be seen in moribund or unstained dead miracidia, and may be best observed with the aid of intra-vitam stains. They do not show in silver impregnated preparations. In the pres- ent work they were studied from surface views of whole mounts, either unstained or stained with neutral red. The nuclei of the first tier of epi- dermal cells are much elongated, measure from 14 /j to 17 n in length and about 2 n in width, and lie very near the posterior border of the cells. Each of the 8 epidermal cells in the second tier contains an elongated but somewhat irregular- shaped nucleus near its posterior border (Fig. 9). These nuclei are 11 n to 13 n in length and 3 ^ in width. Those of the third tier of epidermal cells show the same position, shape and length but are only about 2 ^ in width. Each of the 2 posterior cells contains a centrally located nu- cleus about 14 n long and 5 m wide. As pointed out by Bennett (1936), the nuclei of the epidermal cells have been described for only a few miracidia. With slight variations in shape, size and position, these structures are apparently similar in the miracidia of all the Paramphistomidae in which they have been in- vestigated. In this group Sinitsin (1931) de- scribed them in the miracidia of Paramphistomum cervi, Krull & Price (1932) in Diplodiscus tem- peratus and Bennett (1936) in the miracidia of Cotylophoron cotylophorum. Beneath the surface layer of ciliated epidermal cells is a layer of transparent subepithelial cells. As indicated by their nuclei, these cells form a continuous layer around the internal structures of the miracidium. The nuclei are distributed over all portions of the subepithelial layer, but are more numerous in the anterior half of the body (Fig. 9). In an optical section of a whole mount viewed from the dorsal side, from 13 to 15 subepithelial cell nuclei may be seen along each outer edge of the miracidium. In surface view a group of from 12 to 15 may be seen overlying the “primitive gut” and smaller groups may be identified in the middle and posterior regions of the body. A few of these nuclei appear spherical but most are slightly elongated and vary from 6 n to 7.5 m in length and from 4 n to 5 m in width. Krull & Price (1932) showed that in the mira- cidium of Diplodiscus temperatus these nuclei are arranged in 3 definite rows, and Bennett (1936) found them to be distributed in 4 principal groups in the miracidium of Cotylophoron cotylophorum. Bennett pointed out, however, that not all the nuclei are to be found in these groups. In Zygocotyle lunata , the subepithelial nuclei are distributed irregularly through the subepithelial layer, and while they are more numerous in some areas than in others no definite arrangement into groups could be observed. Actually, examination of different specimens of Z. lunata showed con- siderable variation in number and distribution of the nuclei. Bennett (1936) observed mitosis in some of the subepithelial nuclei in C. cotylo- phorum and he points out the futility of attempt- ing to determine their number. The “primitive gut” is a saccate or flask- shaped structure occupying a considerable portion of the anterior region in the miracidium of Z. lunata. Its shape is exceedingly variable both in developmental stages within the egg (Figs. 4, 5) and after hatching of the larva. It may be elongated and narrow or it may be con- stricted transversely, or it may shorten and become very broad. When elongated it extends past the middle of the body and when shortened it occupies only the first third of the body. No lumen in the ordinary sense of the term is present and it is completely filled with a fluid containing a coarsely granular material which surges back and forth actively due to contraction of its walls and of the body of the miracidium. Anteriorly it tapers and seems to terminate blindly just behind the apical papilla. No opening to the outside could be found and nothing was observed to be either taken in or extruded from it. Its walls show no cell boundaries in the mature miracidium. Four large, somewhat ovoid nuclei, measuring about 8 n long by 5 m wide, are situ- ated near the posterior end, where they may be seen at all times since they remain attached to the wall and do not surge about with the granular contents of the sac (Figs. 5, 9). Most helminthologists have considered the “gut” of the miracidium as a primitive or ves- tigial intestine but more recently the work of Reisinger (1923), Manter (1926), Price (1931), Lynch (1933), and Bennett (1936) seems to suggest that this structure is a gland rather than a gut. Bennett (1936) says, “The development of the primitive gut at some distance from the anterior end of the body, the size of the cells and their nuclei, the early development of the granu- lar contents, the absence of a definite cell wall around each nucleus after the four-cell stage is reached, the concentration of cytoplasm around 1941] 71 Willey: The Life History and Bionomics of Zygocotyle lunata the nuclei at the posterior end of the gut, the absence of a mouth and a lumen, and the com- plete disappearance of the contents immediately after penetration of the miracidium into the snail host while the nuclei may still be identi- fied— all give evidence in favor of interpreting this structure as being a gland rather than a gut. ” The writer is inclined to agree with the opin- ions of the above-mentioned workers that the so-called “primitive gut” is probably glandular in its function, but more intensive studies on the embryonic origin and the fate of this structure will have to be conducted before final decision can be made as to its nature. If it functions in the penetration of the larva into the snail host, an opening must develop at that time, and the granular contents may consist of secretory granules formed in a structure which might be homologous with a gut in other forms. The excretory system of the miracidium of Z. lunata resembles that described for other mem- bers of the Paramphistomidae. Two large flame cells, one on each side, measuring from 13 u to 15 ju in length of flame and from 6 u to 7 u in width, are located just anterior to the middle of the body (Figs. 6, 9). Each possesses a large spherical nucleus at the base of the flame. A collecting tubule passes posteriorly in loose coils from each flame cell to a level behind the excre- tory pores, then loops forward to encircle the flame cell and again passes back to open at the excretory pore, which is located laterally just in front of the junction of the third and fourth tiers of epidermal cells (Fig. 8). A large spherical vesicle lies just anterior to each flame cell in the miracidium during late development in the egg as well as after hatching (Figs. 5, 6). However, no morphological association could be estab- lished between them and the excretory system. No accessory excretory cells as described for the miracidia of Heronimus chelydrae by Lynch (1933) and no duct nucleus as reported for that of Diplodiscus temperatus by Ivrull& Price (1932) could be found in the miracidium of Z. lunata. Krull & Price (1932) and Bennett (1936) re- ported 2 pairs of penetration gland cells in the miracidia of D. temperatus and C. cotylophorum respectively. They described these glands as 4 unicellular units extending from the base of the apical papilla backward for about one-fifth of the body length, with nuclei at their posterior ex- tremities. From the descriptions and figures, the 4 ducts which open anteriorly are each a part of one of the 4 gland cells. No indication is given concerning their role in penetration. In the present material of Z. lunata, 2 nuclei with clear areas around them were found on each side at a level near the junction of the first and second rows of epidermal cells. These nuclei, slightly ovoid in shape, were about 4 ^ in length. In spite of repeated observations on different miracidia at different stages of development, it was not possible to find any ducts leading an- teriad from these clear spaces around the nuclei. The greater portion of the posterior half of the miracidium is occupied by germinal tissue, which consists of about 40 germ cells as evidenced by their large spherical nuclei which measure from 5 m to 8 m in diameter. In all miracidia observed after hatching, one or more germ balls were present in addition to the germ cells. Most of the larvae contain one large germ ball measuring 25 n across and consisting of about 16 cells with a definite membranous covering. This germ ball lies in the anterior half of the body behind the “gut” and between the flame cells. In some specimens an additional smaller germ ball could be identified. The germ balls and the larger germ cells lying in the central cavity of the miracidium appear to be completely free and not attached to any other structure. The nervous system consists of nerve cells and fibers in association with a large ovoid mass lying dorsal to the “gut” and sending out pro- cesses laterally and posteriorly. Other processes probably extend forward but these were not observed. The dorsal nerve mass contains cells and fibers and measures about 25 m by 30 n- Large lateral processes could be observed in living miracidia while confined in the egg as well as after hatching. They could be traced to the body wall and were then lost. Very small cells, visible only with the aid of intra-vitam stains, lie scattered about outside of the central nerve mass. Two papillae protrude laterally through open- ings between the ciliated epidermal cells at the level of the posterior border of the first tier of epidermal plates (Figs. 7, 8). They have been observed in numerous other species and have been variously called lateral papillae, anterior papillae, lateral processes and anterior ducts by different authors. They are probably sensory in function since in some forms they are described as being associated with the central nerve mass. They are about 6 m in diameter and their position between the epidermal plates is clearly shown in silver impregnations by large round spaces. Smaller but similar spaces appear at other points of union between the first and second tiers of cells, but no structural units associated with them could be identified in Z. lunata. Lynch (1933) observed a number of small motionless bristles in this position in the miracidia of Heronimus chelydrae. Experimental Infestation of the Intermediate Host. The intermediate host in the life cycle of Zygocotyle lunata is the snail Helisoma antrosum. Naturally infected snails of that species provided the cercarial stage from which the adults were obtained and the complete life cycle demon- strated. Laboratory-raised snails were experi- mentally infected with miracidia developed in eggs from feces of experimentally infected ducks and rats. Helisoma antrosum reproduces readily in the laboratory at all seasons of the year and was available in stock tanks at all times. All snails used in the infection experiments were laboratory-bred. Miracidia were strongly at- tracted to the snails, to pieces of snail or to snail 72 Zoologica: New York Zoological Society [XXVI: 13 feces. To collect the rapidly-swimming mira- cidia from a dish, it was only necessary to place a snail in the dish and by the time one could place the dish on the stage of the microscope and focus on the snail, the miracidia would have gathered around it. They swim under and over and around the shell, occasionally attaching momentarily to the foot, edge of the mantle or to the shell, and then break away again and attach at some other point or even swim away to a different snail. If a snail is removed from the dish before penetration has occurred, the miraci- dia are attracted by the mucus left behind by the snail. No response to light could be observed. If no snail is present in the dish, the miracidia swim for periods up to 7 hours, settle to the bottom of the dish, and they may swim there in a narrow circle for a short time until death ensues. Miracidia were observed with snails for vary- ing lengths of time. In some cases miracidia disappeared under the shell within 15 minutes. Long and careful search failed to find them again and either they had penetrated or had been caught in the mucus secreted by the snail. This procedure was observed repeatedly, the time required for this apparent penetration varying from 15 minutes to 2 hours. In two cases, miracidia were seen to enter the space within the shell and attach to the base of the foot in a posi- tion perpendicular to it. Little progress, if any, toward penetration had occurred after one hour when observation was discontinued. In all the early attempts to infect Helisoma antrosum, medium sized snails from 8 to 10 mm. in diameter were exposed individually in separate finger bowls to 1 to 15 miracidia. Nineteen snails were thus exposed between January and June, 1938, but none of the snails became in- fected. After observing the apparent penetration of the larvae into the snails, successful infections were fully expected and no explanation could be offered for the negative results. On June 29, the writer, preparing to leave for Woods Hole, dumped about 40 eggs which were due to hatch 2 days later, into a battery jar containing some very young laboratory-raised snails. Another batch of 70 eggs of Z. lunata due to hatch July 8 was placed in a 2-gallon aquarium jar containing laboratory-raised snails of various sizes. Re- turning to the laboratory on August 17, the writer found encysted metacercariae on the glass in both jars. Isolation of the 42 snails showed 9 infestations, all but one of which were in snails 7 mm. or less in size. The single larger infected snail was 13 mm. in diameter. On August 27, 20 eggs of Z. lunata with miracidia ready to hatch were put into a finger bowl with 3 very young snails, each being about 2 mm. in diameter, and 35 days later 2 of the 3 snails began giving off cercariae. Young snails from 2 mm. to 6 mm. in size were used in all later experimental infections. Mass infections using large numbers of miracidia in small aquarium jars containing from 20 to 75 snails were much more successful than when a single individual was exposed to a few miracidia in a separate dish. In such mass infections, from 10 per cent, to 55 per cent, of the snails became infected. Not less than 80 successful experimental infesta- tions of Helisoma antrosum were obtained in which mature cercariae were produced. Many other experimentally infected snails were killed for ■ dissection or sectioning during the early stages of the infestation. The miracidium meta- morphoses in the snail into a sporocyst which in turn produces rediae. The redial generation gives rise to cercariae which emerge from the snail from 32 to 49 days after penetration of the miracidium. The snail host may carry an infestation with Z. lunata for long periods. The 4 naturally in- fected snails from which the life history studies began were collected in September and October, 1937, at which time they were giving off cercariae in numbers up to 100 per day. Of these, one died on December 29, 1937, 2 others died in April, 1938, and the 4th, which was recorded as a light infestation the previous September, lived until June 25, 1938. During this period they were kept isolated in finger bowls and fed lettuce leaves, and the water was changed about once a week. Many thousands of cercariae were pro- duced. Some of the experimental infections per- sisted equally long. From a group of 12 snails which began giving off cercariae on December 18, 1938, seven were still living in the laboratory and shedding cercariae after 9 months. From a size of not more than 5 mm. when infected they had grown to an average size of 15 mm. in diameter of shell. No snails were exposed to miracidia a second time after they were once infested with Z. lunata. None was observed to have lost the infestation and those which were crushed or died naturally after giving off cercariae for 9 months still contained large numbers of immature and mature rediae and cercariae. The larvae infest most heavily the liver and gonads of the snail host but rediae and immature cercariae are found in considerable numbers in the lymph spaces and practically everywhere in the snail except in the lumen of the intestine. None of the snails produced any eggs after becoming in- fected. As seen in sectioned snails, the gonads are reduced to a few shreds of tissue or cannot be identified at all. Sporocyst. The sporocyst of Z. lunata was observed only in the mature condition. Attempts to find early sporocysts by dissection of snails within a few days after exposure to miracidia were unsuccess- ful. Mature sporocysts were found in snails sectioned from 22 to 28 days after penetration of the miracidium. At this stage many rediae and immature cercariae are already free in the tissues of the snail. Usually no sporocysts can be found in an infected snail which has begun to shed cer- cariae, but one snail dissected 47 days after infestation, yielded a sporocyst measuring 297 n in length and 195 n in width which contained a single well-developed redia and nothing else. On manipulation of the coverslip the wall was ruptured and the young redia emerged. All other 1941] Willey: The Life History and Bionomics of Zygocotyle lunata 73 snails dissected later than 28 days after infesta- tion failed to yield sporocysts. No sporocysts of Z. lunata were found in the naturally infected snails studied. The mature sporocyst varies in shape from ovoid to elongate and is broader anteriorly than at the posterior end. It is a simple saccate structure with a body wall consisting of a cuticle, a membranous sheet and muscle fibers. Within the central cavity are germ balls and young rediae in various stages of development. The excretory system is that which is carried over from the miracidium and consists of a pair of flame cells with collecting ducts which open laterally a short distance behind the middle region of the body. A terminal bladder was ob- served on each side. A mature sporocyst found in sections of a snail killed 28 days after penetration of the miracidium contained 2 germ balls at the pos- terior end and 5 young rediae which occupied the central cavity. A reconstruction of this specimen is shown in Fig. 10. Each of the contained rediae shows a well-developed pharynx and an intestine which occupies most of the space within the young larva and extends nearly to its posterior border. The pharynx varied in diameter from 23 n in the 2 individuals in the posterior region to 27 m in the young redia near the anterior end. Figure 14 is a photomicrograph of one of the sections of this sporocyst and shows parts of 4 of the 5 rediae. The pliarynges shown are those of the two posteriorly placed rediae. Redia. The redial generation of Zygocotyle lunata was described by Willey (1936) in a paper on Cercaria poconensis. Since Cercaria poconensis Willey, 1930, is the larva of Z. lunata, the mature redia need not be again described here. However, since only naturally infected snails were available for the previous study, no information was ob- tained on the early stages of infestation. With an abundance of material from experimentally infected snails it has been possible in the present investigation to make more complete observa- tions which reveal the presence of daughter rediae. In the earlier description (Willey, 1936) of the stages found in the snail, it was stated that, “All the snails examined showed very many rediae of all sizes, but no sporocysts or mother rediae were found.” Many very small rediae as well as larger ones are always to be found in crushed infected snails, even in those killed 9 months or longer after experimental or natural infestation. This fact indicated strongly the existence of two generations of rediae, since the sporocyst disap- pears early in the course of the infestation. Ac- cordingly, in the present study, experimentally infected snails were dissected or sectioned at different periods following penetration of the miracidium of Z. lunata. Most of the observa- tions were made on living material from crushed snails, but sections of infected snails also show all the more important stages. In some of the snails crushed during early stages of the experimental infestations, mother rediae were found which contained only a single daughter redia and a few undeveloped germ balls near the posterior end. A specimen of this type shown in Fig. 11 was 330 m long and its pharynx measured 33.4 p in diameter. The daughter redia was 198 p in length and its pharynx also measured 33.4 p in diameter. The young redia showed considerable movement within the parent and its intestine extended back more than three- fourths of the length of the body. In this early stage of infestation no cercariae were as yet to be found free in the tissues of the snail, but rediae were also present which contained only devel- oping cercariae (Fig. 15). In a group of snails crushed 20 days after experimental infestation, numerous rediae were present which contained a single daughter redia and 3 to 6 germ balls which were not as yet differentiated. In no case could more than a single daughter redia be identified within a parent redia. Infected snails, killed 25 days or later after penetration of the miracidium, contained mother rediae with one daughter redia and numerous immature cercariae. Few such mother rediae were present in any one snail, but all snails examined between 25 and 47 days following in- festation contained this stage in addition to many rediae in which only cercariae could be observed. The identification of the different larval stages within the same mother redia was unmistakable. The single daughter redia seen in Fig. 13 showed much movement, squirming and turning around actively. The several cer- cariae present were larger and showed no move- ment. The well-defined pharynx in the daughter redia measured about 30 p in diameter, while the oral sucker of a developing cercaria is much larger, when it first becomes definable, than the pharynx of a large mature redia. Further, in some cases the eye-spots of the cercariae had begun to develop. The cones of cilia in the flame cells of daughter rediae are from 11 to 13 p in length, whereas those of cercariae of this species are only from 5 to 7 p long. Mother rediae containing both a daughter redia and cercariae were found in laboratory- infected snails studied during the period from August to March, but it seems probable that rediae are produced singly by mother rediae throughout the course of the infection. This is indicated by the fact that infected snails at all stages of infestation always contain great num- bers of mature and immature rediae of various sizes free in the tissues. They must be produced more or less continuously in the snail host and emerge from the parental generation at a rela- tively early stage. All daughter rediae observed were located in the anterior region of the mother rediae and they are always produced singly. Rediae containing only a daughter redia and no cercariae (Fig. 11) are small and are found only in the early stages of the infestation. Rediae containing both a single daughter redia and cercariae were all older and larger individuals 74 Zoologica: New York Zoological Society [XXVI: 13 measuring from .7 mm. to .9 mm. in length. The redia shown in Fig. 13 was .792 mm. long and contained a daughter redia measuring .335 mm. by .066 mm., while that in Fig. 12 was .860 mm. in length and contained a much younger daughter redia which measured .172 mm. in length and .063 mm. in width. These facts sug- gest the probability that each redia produces one daughter redia and proceeds from that time on to produce cercariae only. This would explain the presence of rediae of all sizes during all stages of the long-term infestation in this species. The rediae move sluggishly when freed from the snail, and in a watch glass usually remain in one place with only slight changes in body shape due to muscular contraction. No locomotor ap- pendages are present at am’ stage. Twelve flame cells are present in the mature redia of Z. lunata while only 6 appear in younger individuals. Most amphistome rediae described show a total of only 6 flame cells in the excretory system of the mature redia. Looss (1892) mentions 4 flame cells on one side in the redia of Diplodiscus sub- clavatus and Krull & Price (1932) figure a total of 7 in that of Diplodiscus temper atus. Looss (1896) described 5 pairs of flame cells in the mature redia of Paramphistomum cervi. A daughter generation of rediae has been described for several species of amphistomes. Looss (1896) reported more than a single gener- ation of rediae in Gastrodiscus aegyptiacus and in Paramphistomum cervi. In life history studies on P. cervi, neither Takahashi (1928) nor Szidat (1936) were able to find any evidence for a second generation of rediae. Beaver (1929) described 2 generations of rediae in Allassostoma parvum. Le Roux (1930) indicated that mother rediae occurred in the life cycle of Cotylophoron cotylo- phorum and Bennett (1936) found one specimen of a mother redia in that species. Krull & Price (1932) reported only one redial generation for Diplodiscus temperatus, but Herber (1938) demonstrated both mother and daughter rediae in that species. The development of rediae and cercariae within the same mother redia is known for only one other species of amphistome, and the present work constitutes the second report of this condition in amphistomes. Looss (1896) described a redial generation of this type in Gastrodiscus aegyptiacus. He figures a redia con- taining 3 daughter rediae and 3 cercariae and states that rediae containing only cercariae are rarely encountered in that species. Some authors have postulated that in certain forms a definite number of rediae and cercariae are produced. In the absence of experiments with known numbers of miracidia infecting the snails, no definite conclusions can be reached in this regard in any species of trematodes. In Zygocotyle, the finding of only small numbers of mother rediae containing single daughter rediae and cercariae together indicates that the produc- tion of rediae is a continuous process and is not limited to a definite number. Variations may occur in the redial generations in the snail under natural conditions accompanying seasonal changes. Experimentally infected snails kept under laboratory conditions do not always afford sufficient information on which to base conclu- sions concerning the prevalence and numbers of the various larval stages. The course of events probably varies with changing conditions. Much work still remains to be done on these problems of development. Cercaria. The cercaria of Zygocotyle lunata was named Cercaria poconensis in an abstract by Willey (1930), and in 1936 he described the redial and cercarial generations together with a report of infestation experiments with the metacercarial stage. The cercaria need not be redescribed here and only additional information not available from the earlier studies will be presented. The material from which C. poconensis was described and that from which the life history of Z. lunata is demonstrated in the present study are unmis- takably identical. The size and the shape and distribution of the body organs in the two groups of specimens agree perfectly. The size measure- ments vary somewhat with different degrees of flattening. For example, the oral sucker in fixed and unflattened cercariae shows an average measurement of .064 mm. in diameter, while in living specimens, flattened under medium pres- sure, it may be as large as .106 mm. across. The oral sucker and oral evaginations together measure .165 mm. in length in fixed, unflattened individuals. Nasmark (1937), in a revision of the Param- phistomidae, has attempted to show that the sucker at the anterior end in amphistomes is a pharynx rather than an oral sucker. On the basis of histological studies, he believes that this structure is homologous with the pharynx of the monogenetic trematodes and the rhabdocoel turbellarians, and states that contrary to the opinion of Looss (1902) and others it should be designated a pharynx. However, due to the incomplete nature of Nasmark’s evidence, the conclusions are not accepted by the present author and the sucker is here referred to as an oral sucker. Fischoeder (1903) referred to the anterior sucker of Z. lunata as a pharynx, causing some misinterpretation in the literature, but all the more recent authors have preferred to call it an oral sucker. Until final conclusive evidence is forthcoming, the terminology currently used seems more desirable. The posterior overhanging lip of the acetabu- lum with its 2 lateral conelike projections (Figs. 21, 22), which are so characteristic of the genus Zygocotyle in the adult stage, were not observed in the earlier studies on the cercarial stage. But after it became known that this cercaria was the larval stage of Zygocotyle, the lip and conical projections were observed from the ventral sur- face of cercariae when under only slight pressure. This modification of the acetabulum is present on the cercaria in an immature condition. Figure 16 is a photomicrograph of a living cer- caria under medium pressure and shows the 1941] Willey: The Life History and Bionomics of Zygocotyle lunata 75 relationships of the various organ systems. The characteristic branching of the main excretory ducts is clearly outlined by the presence of ex- cretory concretions. Drawings from both living and fixed material of redial and cercarial genera- tions appear in the earlier description (Willey, 1936). The cercaria leaves the redia while still in a very immature condition. The intestine, oral sucker, acetabulum, eye-spots, tail rudiment and the excretory system, already laid down while the cercaria is in the redia, continue their devel- opment after emergence. Some variation occurs in the size and degree of differentiation of the cercariae at the time of emergence. Young cercariae are frequently observed free in the tissues of the snail which have not developed as far as other cercariae which are still within nearby rediae. In experimental infestations, young cercariae were first found free in the tissues of snails crushed 16 days after exposure to miracidia. In other snails, crushed 20 days after exposure to miracidia, none had as yet emerged from the rediae. The rate of development is known to vary with temperature conditions. The time required for the complete development of the cercaria, from penetration of the miracidium until shedding of the first mature cercaria from the snail, varied in the laboratory from 32 days during the warmer months to 49 days during the winter. After emergence, cercariae swim about vigor- ously in the water at the side of the container toward the light for 30 minutes to 2 hours. They respond very rapidly to changed lighting condi- tions and will follow a beam of light moved about from one side of the dish to the other. Encyst- ment occurs on the side of the dish toward the light, on the shell of the snail, or occasionally on vegetation. If handled or otherwise irritated they encyst almost immediately, often attaching and encysting within a dropper when being transferred to a slide for examination. If placed on a slide in a small amount of water, a coverglass must be added immediately to prevent encyst- ment. The shell of a snail producing cercariae is usually crowded with encysted metacercariae. Cercariae emerge in greatest numbers between 10:00 A. M. and 2:00 P. M. and usually only on bright days. On dull, rainy days very few or none escape, while on bright, sunny days as many as 100 may emerge from a single infected snail at the peak of the infestation. Cercariae may be produced from an infected snail for 9 months and longer, but the number of cercariae escaping each day decreases as the snail remains longer in the laboratory. Little difference could be ob- served between the numbers of cercariae pro- duced in naturally and experimentally infected snails. Metacercaria. The cercaria encysts and passes into the meta- cercarial stage in which it awaits ingestion by the final host. The process of encystment is very rapid. The cercaria attaches itself by means of its suckers, the tail vibrates from side to side somewhat more slowly than in swimming, and the body appears to undergo rapid squirming movements. Cystogenous material then oozes out rapidly over the surface of the body from the elliptical cystogenous granules which occupy most of the dorsal half of the cercaria. The cyst wall forms rapidly and the tail is left attached to the outside of the cyst, where it lashes violently for an hour or more and then drops off, sinks to the bottom and may continue lashing about for several hours. The body of the cercaria twists and turns about during the process as though molding the inner wall of the cyst. Finally the cyst wall hardens, the metacercaria coils about in the cyst and after several hours becomes rela- tively motionless with suckers apposed, periodi- cally undergoing slight twitchings and contrac- tions in various regions of the body. The cysts are large dome-shaped hemispheres with thick resistant walls which are brown to black in color when seen with the naked eye. The base of the cyst flares out slightly from the margin of the cyst proper (Fig. 18). When formed on glass they are flat on the bottom and the greatest diameter shows an average measure- ment for 10 metacercariae of .368 mm. The diameter at the base of the dome varies in 10 individual cysts from .277 mm. to .343 mm., the average being .289 mm. Figure 19 is a photo- micrograph of a 10-day old metacercaria which has been dissected from its cyst. When removed thus in water or salt solution, they contract and undergo little or no movement. Much black pigment is present in the body wall and this tends to obscure the internal structures, which show no advance in development over the condition found in the cercaria. The black pigment of the eye-spots and body persists throughout meta- cercaria] life and scattered granules of eye-spot pigment are still present after 3 weeks of devel- opment in the final host (Figs. 21-23). Infestation Experiments with Metacercariae. Early attempts to infest the final host with the metacercaria of Z. lunata were conducted, using cold-blooded hosts. As outlined by the writer in an earlier paper (1936), encysted metacercariae were fed to tadpoles but all the experiments were negative. In 1937, following unsuccessful at- tempts to infest turtles with the larvae, some of the metacercariae were dissected from their cysts and placed in cold Ringer’s fluid at 20° C. All were dead after 3 hours. Artificial digestion of some of the metacercariae from their cysts with pepsin and pancreatin solutions at 37° C. indi- cated that the final host was a warm-blooded animal. Under this treatment the cyst walls became soft and movement of the metacercaria was observed after 4 hours. After 10 hours and up to 20 hours of artificial digestion, young worms were still alive in the cysts while others showed much activity on being released from the cyst. Consequently on October 8, 1937, 2 young laboratory-raised rats were each fed about 65 76 Zoological New York Zoological Society [XXVI: 13 metacercariae obtained from the naturally in- fected snails as described earlier in the paper. Five days later one of the rats was killed and yielded 59 young worms in the cecum with none above or below this level in the intestine. De- velopment had proceeded far enough to permit identification of the worms as Zygocoiyle. The small cone-like projections on the posterior edge of the acetabulum are well developed at this stage (Fig. 20). The worms, still immature, show average measurements for 10 of them of .940 mm. in length and .460 mm. in width. The common natural hosts of Zygocoiyle are various species of ducks. Thirteen young ducks were subsequently fed varying numbers of cysts and all became infected. Similarly, in the course of the investigation, more than 60 rats and one ram were experimentally infested. Attempts to infect pigeons and rabbits gave negative results. In order to determine the time required for the young worms to mature in the final host, fecal examinations were conducted almost daily on some of the experimental hosts. Two ducks, (nos. 1 and 3) fed metacercariae on October 14, 1937, began giving off eggs of Zygocoiyle in fecal material on November 24, or on the 41st day of infestation. Duck number 3 was killed 5 days later and contained 7 mature specimens of Zygocoiyle lunata, 5 in one cecum and 2 in the other. Similarly 4 rats (nos. 3, 4, 5 and 6) were fed from 30 to 40 encysted metacercariae each on October 14, 1937. On November 24, when the 2 ducks described above showed eggs in the feces, the rats were still negative. One rat, number 5, killed on November 28, the 45th day, contained 23 Zygocoiyle, several of which showed a few eggs in the uterus near the ovary, but none was fully mature as yet. Eggs of Z. lunata from this series of rats first appeared in the feces of rat number 6 on the 46th day after infestation. This rat was killed on December 4, the 51st day after the experimental feeding, and contained 8 fully mature Zygocoiyle lunata in the cecum. The more rapid development in the duck may pos- sibly be due to the higher body temperature maintained by that host. This difference was confirmed in other series of infected rats and ducks, the data for which will be described later. Thus, beginning with cercariae from naturally infected snails, all stages in the development of the adults of Zygocoiyle lunata were obtained in rats and ducks. As described in the earlier sections of the present paper, eggs from feces of the experimental hosts were embryonated to produce miracidia which were experimentally introduced into laboratory-raised snails. In the snail, Helisoma antrosum, the sporocyst and the redial and cercarial stages were obtained and the complete cycle was carried out several times in the laboratory. Experiments on Injectivity of Metacercariae. After encystment the metacercaria remains quie- scent and awaits ingestion by the final host. No development occurs within the cyst. Metacer- cariae dissected out or freed from their cysts by artificial digestion after one day of encystment are in no way distinguishable from those similarly freed after 20 or 30 days. This observation was confirmed by feeding experiments with rats. Cysts in a few drops of water were placed on small pieces of bread and given to the rats after withholding all food for 24 hours. In an experi- ment conducted on December 30, 1937, rat 22 was fed 100 metacercariae which were 14 days old and rat 25 was fed 100 metacercariae which were 85 days old. Both rats were killed 15 hours after ingesting the larvae and each rat yielded more than 30 excysted worms in the cecum. Some larvae were still within their cysts and none could be found anywhere in the digestive tract other than in the cecum. No significant differ- ence could be detected between the two groups of young worms. All were equally active and the number of worms found was approximately the same in the two hosts. In an experiment de- signed to detect any changes which might occur immediately after encystment of the metacer- caria, rat 12 was fed 50 newly encysted larvae, some with the cercarial tail still attached and the cyst wall still soft, and rat 11 was fed 70 meta- cercariae which were 47 days old. Both rats were killed 3 days later and yielded young worms in the ceca which were practically indistinguish- able morphologically in the two hosts. Thirty- five worms were collected from rat 12 which re- ceived 50 newly formed cysts and 60 worms were obtained from rat 11 which received 70 cysts 47 days old. A few cysts are probably destroyed by the rat in the chewing of the bread. In a third experiment, one rat (no. 23) was fed 15 metacercariae which were 2 days old and 15 which were 32 days old. This rat was killed 6 days later and the 20 young worms collected from the cecum showed no significant differences in size or degree of differentiation. The rate of development of Zygocotyle lunata to sexual maturity is not correlated with the age of the metacercaria at the time of its ingestion. These experiments show conclusively that no develop- ment occurs in the cyst of Z. lunata and also that the encysted metacercariae are infective im- mediately after encystment. Longevity. In one of the foregoing experi- ments, metacercariae, encysted for 85 days, were viable when fed to rat 25. In a series of longevity experiments, it was determined that the meta- cercaria will live much longer than that. En- cysted metacercariae were kept at room tem- perature in the laboratory in covered finger bowls attached to the glass wall where first deposited, and the water was not changed except to add water occasionally to make up for evapo- ration. Metacercariae not older than 3 months were viable and when fed to rats produced in- festations with Z. lunata. Encysted larvae older than 4 months gave variable results (Table 2). The oldest metacercariae which successfully produced an infection in rats had been in the laboratory for 138 days. In this experiment rats 48 and 49 were each fed 50 metacercariae from cercariae emerged from snail number 2 on Janu- ary 30, 1938. Movements of the larvae within 1941] 77 Willey: The Life History and, Bionomics of Zygocotyle lunata Table 2. Longevity of encysted metacercai’iae of Zygocotyle lunata. Host and date Age of Number of Elapsed time Number of of feeding metacercariae metacercariae before killing worms metacercariae in days ingested host (Days) recovered Remarks Rat 34 June 2, 1938 86 10 11 3 Rat 35 June 2, 1938 86 10 11 8 Rat 30 Feb. 3, 1938 121 100 46 0 Movement observed in cyst before feeding to rat Rat 29 Feb. 3, 1938 131 100 46 0 Movement observed in cyst before feeding to rat Rat 46 June 9, 1938 130 50 9 23 Movement observed in cyst before feeding to rat Rat 47 June 9, 1938 130 50 9 28 Movement observed in cyst before feeding to rat Rat 48 June 17, 1938 138 50 169 1 Eggs in feces after 74th day Rat 49 June 17, 1938 138 50 169 2 Eggs in feces after 74th day Rat 63 Feb. 10, 1940 152 50 14 0 Cysts shrunken Movement in 10% Rat 44 June 4, 1938 166 150 9 0 Cysts not examined Rat 45 June 4, 1938 166 150 9 0 Cysts not examined Rats 64, 65, 66, 67 Feb. 29, 1940 171 25 each 5-10 0 Cysts shrunken No movement observed the cyst were observed before feeding. Seventy- four days later many eggs of Z. lunata were col- lected from feces of both rats and when these 2 rats were killed after 6 months of infestation, large, adult specimens of Z. lunata were re- covered. In a similar experiment with rats 46 and 47 (Table 2), metacercariae 130 days old were fed and when the rats were killed 9 days later, 23 young worms were recovered from the cecum of rat 46 and 28 from rat 47. As indicated in Table 2, cysts 152, 166 and 171 days old re- spectively were fed to rats but no infestations resulted. Some variation in longevity occurs. In the experiment involving rats 29 and 30, no infection was obtained from metacercariae aged 131 and 121 days respectively, although movement was detected within the cyst. Minor variations in other factors would readily account for such slight variations in longevity and infectivity. That these are not due to individual differences in the host reaction is indicated by the fact that in most of the experiments dealing with longevity of metacercariae, 2 host animals were fed similar numbers of larvae produced from the same snail host on the same dates, and in each case the re- sults were always the same in the 2 hosts con- cerned. No evidence is available as to what constitutes optimum conditions for long survival of encysted metacercariae. Bennett (1936) reports that under optimum conditions the metacercaria of Cotylophoron cotylophorum probably lives for several months. In his experiments, he pre- sumably kept them at room temperature and after 3 months (June 5 to September 5) 33 per cent, were still alive. At this point observations were discontinued. Krull (1934) kept metacer- cariae of the same species alive under the same conditions for as long as 5 months from July 2 until December 2. Both of these workers used the criterion of movement of the metacercaria to determine its life span. As indicated by the data on rats 29, 30 and 63 (Table 2), movement in the cyst shows the metacercaria of Z. lunata to be alive as long as 5 months, but such larvae, when fed to the final host, were in these three attempts unable to survive conditions within the final host. It seems probable that motility is not a valid criterion of infectivity. Experimental Studies on Viability of Meta- cercariae. Experimental feedings conducted with rats show that at least 85 per cent, of the meta- cercariae of Z. lunata excyst and survive for a time in the final host. The percentage of viable metacercariae is probably higher since some of the cysts may be destroyed in the chewing proc- ess by the rat host. The number of meta- cercariae which have excysted and are recover- able as young worms is seen to be very high if the host is killed within the first few days after ingestion of the cysts, because, as will be shown later, the host may begin to lose some of the worms as early as the second or third day. Table 3 shows the number and percentage of worms obtained in 10 experiments in which the hosts were killed within the first 11 days. The high percentage of viability of metacercariae is shown in feeding experiments with ducks as well as rats. For example, duck 3a, fed 150 encysted larvae and killed 11 days later, yielded 144 young worms in the ceca. 78 Zoologica: New York Zoological Society [XXVI: 13 Table 3. Viability of encysted metacercariae of Zygocotyle lunata. Metacercariae 73 bfi O ingested by host co .2 & s O -3 <D Host u <D •O 0 3 £ Age (Days) Days ela before ki host Number worms recoverei Percenta worms recovere* Rat 7 90 12-18 2 85 94.4 Rat 11 70 47 3 60 85.7 Rat 12 50 0-2 hrs. 3 35 70 Rat 1 65 8 5 59 90.7 Rat 23 30 2-32 6 20 66.6 Rat 6a 60 1-3 7 55 91.6 Rat 6b 80 30 7 74 92.5 Rat 3 30 11-14 11 25 83.3 Rat 36 75 10-30 11 60 80 Duck 3a 150 9-16 11 144 96 Average percentage of viability over 11 days 85% In order to determine the effect of low tem- perature on metacercariae, a finger bowl con- taining several hundred larvae encysted on the glass was placed outside on a window sill on March 2, 1938, for 11 days, during which time the temperature varied from 8° Fahrenheit to 45° F. During the night of March 3 the temper- ature dropped to 8° F. and the water in the dish was frozen solid for at least 15 hours. The dish was then brought into the laboratory, and as the ice melted the cysts came loose from the wTall of the dish and fell to the bottom. They were examined several hours after all the ice had melted and were found to contain living meta- cercariae actively moving within the cyst. About 120 of these metacercariae were fed to rat 31 which was killed 16 days later. Eighty 16-day old worms were recovered from the cecum. The rest of the cysts had been again placed outside, exposed to freezing temperatures almost every night. After 10 days of such exposure, some were fed to rat 33, which, when killed 11 days later, showed only 6 worms in the cecum. The experiments demonstrate that encysted meta- cercariae of Z. lunata are able to withstand complete freezing of the water around them for at least 15 hours and that some are still viable after 10 days of alternate freezing and thawing. This phase of the problem was not carried further because consistently low temperatures were no longer available. The metacercariae of Z. lunata are unable to withstand prolonged drying. A finger bowl con- taining several hundred viable larvae (30 days old) encysted on the glass was left uncovered without water in the laboratory on March 2, 1938. Twenty-four hours later a few cysts were scraped off and examined and the larvae still looked normal and showed occasional movements. After 48 hours, more were removed and although the metacercariae looked normal no movement was observed. Water was again placed in the dish and metacercariae examined on the next day still showed no movement. One hundred of the cysts were fed to rat 32 which when killed 16 days later contained no worms. Apparently the encysted metacercariae do not survive for long when exposed to the air. Development in the Final Host. Observations recorded in the literature on development of amphistomes in the final host are very fragmentary, consisting of only a few scattered and incomplete reports. In the present study, an attempt is made to investigate this stage in the life history rather completely since the experimental hosts, rats and ducks, are favorable for such studies. These hosts show practically a 100 per cent, susceptibility to in- fection with metacercariae of Zygocotyle lunata. All the ducks (13) fed became infected on the first experimental feeding, as did all the rats (more than 60) except those few which were fed metacercariae shown experimentally to be not viable. Both rats and ducks were given the encysted larvae in a few drops of water which was soaked up in small pellets of bread. The pellets were pushed down the throats of the ducks, and the rats after having food withheld for 24 hours ate the bread readily. In some cases the piece of bread was moistened with milk to hasten its ingestion by the rats. Apparently few of the cysts were destroyed in the chewing process, for as described previously, at least 85 per cent, of the metacercariae developed in the experimentally-fed rats (Table 3). The single sheep (an adult ram) which became infected with Z. lunata did not take the infesta- tion on the first feeding. On October 21, 1937, the ram was given 109 viable metacercariae which were mixed with a handful of moistened oats in a porcelain evaporating dish. The cysts stuck to the moist oats and were undoubtedly ingested. Ten fecal examinations were made between November 26, 1937, and March 1, 1938. All were negative. The cysts may have been destroyed in the chewing process. On March 3, 400 metacercariae were placed in a small amount of water in an evaporating dish. Since the ram had been deprived of water for 48 hours he drank the water and swallowed most of the cysts. He was similarly given 600 metacercariae two days later. In three examinations conducted on May 19, 21 and 26, eggs of Z. lunata appeared in con- siderable numbers in the feces. Since the rain was being used for other experiments, no oppor- tunity was afforded to follow the course of the infestation or to obtain the worms. Therefore, this host record rests entirely on the presence of eggs of Z. lunata in the feces. However, since thousands of eggs of this species had been col- lected and studied from the rats and ducks during this period, little, if any, possibility of error in identification of the eggs exists. The only other flatworm to which the ram was exposed was the tapeworm, Moniezia. It also carried nematode worms, as evidenced by the presence of nematode eggs in the feces from time to time. Two pigeons were each fed 50 viable meta- cercariae on October 23, 1937. Fecal examina- tions were consistently negative, and, when on 1941] 79 Willey: The Life History and Bionomics of Zygocotyle lunata January 29, 1938, both were killed, no worms were found. Similarly a rabbit fed metacercariae showed no eggs of Z. lunata in the feces and no worms were found when it was killed 58 days later. No attempts were made to infest other pigeons and rabbits. In nature, the final host becomes infected with Z. lunata by ingesting the encysted larva from pond weeds, or ducks may eat small snails, the shells of which bear encysted metacercariae. In the laboratory, the snails, both naturally and experimentally infested, and other snails which may be in the same dish, become encrusted with many cysts. The 3 cysts shown in Fig. 18 are held together by an underlying piece of thin snail shell on which they were deposited. Simi- larly some of the uninfected Helisoma antrosum collected along with those naturally infected carry a few cysts on their shells. Excystment probably does not occur in the upper intestine. Rats 22 and 25 were each fed 100 viable encysted larvae on December 30, 1937, and were killed fifteen hours later. In both cases examination of the small intestine yielded no young worms or encysted larvae in that region. In the cecum many newly excysted worms, most of which were not yet attached to the wall of the cecum, were found. Only 30 were collected from each of the hosts, although many more were present. The ceca of both rats contained numer- ous metacercariae which were still encysted. In rat 22, 25 were collected and these when dis- sected out from within the softened cyst wall were alive and active. From this observation and the fact that at least 85 per cent, of the metacercariae regularly excyst and develop for at least several days in the final host (Table 3), it seems apparent that excystment usually occurs in the cecum in rats. No evidence on this point is available for ducks. Zygocotyle lunata occurs normally as a parasite in the cecum of certain water birds, and has been reported from the cecum in the ruminants, Cervus dichotomus, by Diesing (1836), and Bos taurus, by Price (1928). In the present studies, specimens collected from experimentally infected ducks were always found in the ceca except for one worm in the bursa of a duck killed 14 days after infestation. No specimens were present in the intestine of any of the ducks examined. In the experimental rats the worms were usually found only in the cecum, but in each of 2 cases, 2 worms were found in the large intestine. In agreement with the opinion of Gower (1938), it is believed that the intestine in birds is an ab- normal habitat for Zygocotyle, and that the para- sites merely move out of the cecum after the death of the host. Specimens located in the large intestine of the rat are on the way out of the host in the normal reduction of numbers that occurs. As will be described later in the present paper, the parasites are still intact when extruded with the feces. The worms were usually found within one inch of the distal ends of the ceca in freshly killed ducks. Table 4. Experimental infestation of ducks with Zygocotyle lunata. T3 bfl a O <d W'O.S z a — • *-> 'ri W <D a * 1, 10/14/37 50 2, 10/14/37 50 3, 10/14/37 50 4. 10/30/37 100 10/14/37 1? 5, 12/13/37 5 la, 11/20/37 100 2a, 11/20/37 100 3a, 11/20/37 150 4a, 11/20/37 60 5a, 11/20/37 60 6a, 11/20/37 60 12, 7/18/39 100 13, 7/18/39 100 41 744 0 (Eggs in 10/28/39 feces on 10/26/39) — 14 4 41 47 7 — 14 6 — 31 1 — 7 1 44 359 2 44 56 17 — 11 144 — 286 10 — 507 5 — 711 3 42 — — 42 ■ — — Some variation exists in the time required for Z. lunata to develop to sexual maturity. In ducks, they develop more rapidly than in rats. As indicated by the earliest appearance of eggs of Z. lunata in the feces, ducks 1 and 3 contained sexually mature worms at 41 days, ducks 12 and 13 at 42 days, and ducks la and 2a on the 44th day after experimental infestation (Table 4). A greater amount of variation was observed in the time elapsed before appearance of eggs in the feces of the rat hosts. As shown for 6 of the rats in Table 5, the required time varied from 46 to 61 days. The rate of development is influenced to some extent by the number of worms present. Rat 6, in which the worms developed to maturity most rapidly, harbored only 8 large, mature specimens when killed five days after the first appearance of eggs in the feces. On the other hand, rats 8, 10 and 15, in which from 58 to 61 days were required before eggs appeared in the feces, harbored 23, 30 and 34 specimens respec- tively, when killed a few days later (Table 5). Rats 8 and 15 contained some specimens which were still not quite mature and contained no eggs in the uterus. The variation is probably related to the large number of worms present, since, as will be shown later, the rate of development is influenced by crowding. When only a few speci- mens are present, they tend to be all of the same size and at the same stage of development, whereas in hosts harboring many worms, the size and rate of development vary considerably. For example, rat 15, killed 70 days after a single feeding of metacercariae, contained 34 specimens of Z. lunata which after fixation varied in length from 3.4 mm. to 5.4 mm. and in width from 1.5 mm. to 1.9 mm., and some were not yet sexually mature although as stated above, eggs were present in the feces ten days earlier, indicating that some were mature at that time. The faster rate of development of Z. lunata to 80 Zoologica: New York Zoological Society [XXVI: 13 Table 5. Reduction in number of worms with increase in age of infestation in rats. Metacercariae ingested by host (D • cS O 5 SliS « A A < s 26 150 20-30 4 30 10-14 5 30 10-14 6 30 10-14 8 70 12-18 10 70 12-18 15 50 20-40 13 50 20-40 14 50 20-40 48 50 138 49 50 138 37 75 10-30 38 75 10-30 39 75 10-30 40 75 10-30 41 75 10-30 42 75 10-30 43 75 10-30 16 50 20-40 17 50 20-40 18 50 20-40 19 50 20-40 20 50 20-40 21 50 20-40 60 50 ? 52 50 ? 58 50 20-30 50 50 7 28 100 20-30 62 50 20-30 Mature, first eggs in feces (days) Days elapsed before killing host Number of worms recovered 22 120 23 25 45 23 46 51 8 58 59 23 61 61 30 60 70 34 92 28 92 2 169 1 169 2 184 2 184 0 184 3 184 3 184 0 184 3 184 3 193 0 193 0 193 5 193 0 193 0 193 3 226 4 238 2 53 343 2 424 1 711 1 49 co 13 E £ £ O P4 O 80 83.3 76 26 32 42 68 56 4 2 4 2.6 0 4 4 0 4 4 0 0 10 0 0 6 8 4 4 2 1 sexual maturity in clucks is related not only to the higher body temperature of the bird host, but also to the fact that the ducks harbor fewer parasites of this species than do the rats. In in- fected rats, killed any time up to the 11th day after infestation, most of the worms are still present, but after that a gradual loss of worms occurs (Tables 3, 5). In ducks the results are not uniform with regard to the percentage of worms remaining at different ages of the infesta- tion (Table 4), but this is probably due to the fact that variable numbers of metacercariae reach the ceca of the bird, many being eliminated because of this failure to reach the normal site for development. From the data on number and size of worms present at the time when they reach maturity, specimens of Z. lunata are fewer and larger, and they mature more rapidly in the duck than in the rat. Although large numbers of worms may be present early in an infestation (Table 3), rela- tively few persist for long after sexual maturity is attained. In 20 of the rats listed in Table 5 the infestation was older than 100 days when the host was killed. Not more than 5 were found in any one rat and the usual number was 2 or 3. In 6 of these cases, rats killed 181 or 193 days after infestation harbored no worms at that time although all had shown eggs of Z. lunata in the feces at an earlier date. These 6 rats are the only ones from which all the parasites were eliminated. The number of worms remaining in the host after a long period is not related to the number of metacercariae ingested. In old in- festations, the hosts which received only 30 metacercariae harbor just as many worms as those which ingested 100 or more cysts. In the experimental ducks the parasites also occur in small numbers in the older stages of infestation, from 3 to 5 being found in infestations that are from 300 to 711 days old (Table 4). Records in the literature of the collection of Z. lunata from naturally infected bird hosts like- wise indicate that this species after reaching maturity occurs in only small numbers. Fischoeder (1903) in a redescription of Natterer’s original material from the Vienna Museum, had for comparison 2 specimens from Cervus dichotomus and 2 from Anas moschata. Stunkard (1916) recovered 8 specimens from a duck, some of which were small and newly matured, and Price (1928) reports the presence of from 1 to 6 specimens in each of 4 species of water birds. Gower (1938), in reporting collections of Z. lunata from 7 species of water birds from Michi- gan, states, “In no case have more than four of these worms been present in any host other than the artifically infected one.” He had recovered 46 immature Zygocotyle which were 2 weeks old from an artificially infected duck. Price (1928) reported an infestation of Z. lunata in a cow, Bos taurus, which yielded 30 specimens, but many of the worms were immature. On the basis of a comparison of relative size of acetabulum and other organs with body size, it may be con- cluded that the infestation’ in the cow was prob- ably recently acquired and that it could have arisen from a single ingestion of metacercariae. Little is known regarding the nature of the process of reduction in number of worms in the host. That phase of the problem, involving host-parasite reactions of a local or general nature, aside from the simple effects of crowding, is not included in the present study, but the evidence for some mechanism of host resistance is certainly apparent. Stoll (1929), working with the nematode Haemonchus contortus, was the first to show that following the acquirement of an initial infestation, a “self-cure” occurred, accompanied by a high degree of protection from further infection. He suggested that other helminthic infections might show a similar host response. The evidence for “self-cure” and resistance is presented for Zygocotyle lunata in the present studies. Immunity. An established infestation with Zygocotyle lunata in ducks and in rats prevents a superinfestation with this species. Eight at- tempts were made to superimpose a second infes- tation. Table 6 shows the results of experiments involving 5 ducks and 3 rats. Following a single experimental feeding with metacercariae of Z. lunata, a second feeding of 50 to 150 metacercariae was given after 6 to 261 days of duration of the first infestation. The hosts were then sacrificed 1941] 81 Willey: The Life History and Bionomics of Zygocotyle lunata after periods varying from 4 to 28 days after the second feeding. With the exception of an acciden- tal infestation of one worm in duck 4, no worms were found from the second experimental feed- ings. In each case, as seen in Table 6, parasites from the second feeding would be easily identi- fiable and distinctly different in size from the worms actually found, all of which were from the initial experimental feeding. The number of specimens recovered in the various hosts in these planned experiments varied from 2 to 144. It may be concluded that as few as 2 mature worms of this species will make the host immune to further infestation. Further, the experiment on duck 3a shows that an infestation of 6 days duration will prevent a superinfestation, and the data on duck 4a indicate that 10 worms 261 days old will do the same. No extensive informa- tion is available as to the minimum number of worms of a given age which will be necessary to produce resistance to further infestation, but the data in Table 6 seem to indicate that a few worms of almost any age will probably be effective. days, yielding the 6 worms of the 14-day age and one 31 days old. Four were in one caecum and 3 in the other. The results would seem to indi- cate that a single young worm, 17 days old, is not sufficient to produce resistance to superinfes- tation. This was the only case in which worms were recovered from more than a single feeding of metacercariae. In all other cases the worms obtained were of approximately the same size, any differences being easily within the range of individual variation in growth rate. The metacercariae of a second feeding are released from their cysts and may remain in the host for as long as 4 days. Rat 8, given a second feeding 45 days after initial infestation with Z. lunata, was examined for eggs in the feces 4 days after the second feeding and small worms were recovered from the feces. Three were found in one medicine dropper of material from the bottom of a settling glass. They were from the second feeding of 4 days before but had not de- veloped to a 4-day stage in growth. They were dead when recovered but their organization was Table 6. Data showing immunity to superinfestation with Zygocotyle lunata. First Days elapsed Host killed Worms recovered Worms from experimental before second Days after Days after second Host feeding feeding 2nd feeding 1st feeding Age (Days) No. feeding Duck 3 10/14/37 19 28 47 47 7 0 Duck 4 10/30/37 9 5 14 14 6 0 Duck 4 10/14/37* 17 14 31 31 1 6* Rat 8 11/15/37 45 14 59 59 23 0 Duck 3a 11/20/37 6 5 11 11 144 0 Duck 2a 11/20/37 52 4 56 56 17 0 Rat 14 11/23/37 69 23 92 92 2 0 Rat 6 10/14/37 41 10 51 51 8 0 Duck 4a 11/20/37 261 25 286 286 10 0 * Accidental infestation with 1 worm (See text). No attempt was made to determine whether a single worm from the feeding of a single meta- cercaria would induce the characteristic im- munity, but an accidental infection of a duck may throw some light on the probable result. Duck 4, when killed and examined, was expected to have only 14-day old worms, but it contained 6 of these and 1 worm which was obviously much older. Inspection of the data on this duck showed that it had been housed for part of a day, 31 days before, with 3 other ducks (no. 1, 2, and 3) which had just been given an experimental feeding with metacercariae of Z. lunata. Comparison of the single large worm obtained with other worms of known age definitely establishes it as being 31 days old. Apparently this duck (no. 4), al- though not purposely fed with the other 3 ducks, had accidentally picked up a cyst somewhere in the enclosure, possibly from the bill of one of the other ducks which had been fed by dropping- cysts with water into their throats from a medi- cine dropper. This method was later abandoned in favor of placing the cysts in a pellet of bread, as described previously. Duck 4 was fed meta- cercariae 17 days later and then killed after 14 still intact, and when stained and mounted they were found to have progressed to a 2-day stage of development. The measurements for them are included in Table 7 which compares body size, and the sizes of acetabulum and oral sucker in metacercariae dissected from cysts and in worms of from 15 hours to 7 days of develop- ment. The 3 worms recovered from the feces of rat 8 agree closely in measurements with those of 2-day-old worms from rat 7. Apparently the reaction of immunity against superinfestation begins to be effective almost immediately after excystment of the metacercariae, since the young worms were extruded at a 2-day stage of development on the 4th day following ingestion of the metacercariae. No 4-day-old worms were found in duck 2a which was killed 4 days after a second feeding with metacercariae. The mechanism for this resistance to super- infestation with a metazoan parasite such as Zygocotyle is not entirely clear. The problem has been investigated by Taliaferro (1940), Chandler (1937, 1939) and others. For the literature and a general review of the mechanism of immunity to metazoan parasites, the reader is 82 Zoologica: New York Zoological Society [XXVI: 13 referred to a paper by Taliaferro (1940) in which lie states, “Various investigators, including the speaker (16), have stressed the fact that the immunological mechanisms, both humoral and cellular, operative against the larger parasites are identical with those operative against other infectious and antigenic non-infectious foreign materials. ” 2 worms from the latter host were very much larger, averaging 7.0 mm. in length and 3.2 mm. in width as compared with the average measure- ments of 5.0 mm. X 2.3 mm. for the more numerous worms in rat 13. Inspection of the range in size between these two groups of para- sites demonstrates strikingly the effects of crowding. A similar comparison of the data in Table 7. Comparative average measurements of specimens of Zygocotyle lunata of ages up to 7 days. Length Width Acetabulum Oral Sucker No. of in in Length Width Length Width worms Age of specimen mm. mm. in mm. in mm. in mm. in mm. measured Metacercariae dissected from cysts .495 .201 .171 .165 .063 .059 10 15 hrs. in Rat 22 .516 .198 .174 .164 .082 .082 10 2 days in Rat 7 .772 .260 .243 .230 .099 . 105 10 4 days, from feces of Rat 8 .850 .204 .244 .211 .099 .112 3 3 days in Rat 11 .792 .306 .248 .273 .122 .106 10 5 days in Rat 1 .940 .460 .420 .400 .165 .132 10 7 days in Rat 6a 1.200 .590 .462 .442 .211 .165 10 Table 8. Showing the relation between age, number and size of Zygocotyle lunata in rats and ducks. Days after ingestion of No. of No. of Average Average Range in Range in meta- worms worms length width length width cercariae Host present measured in mm. in mm. in mm. in mm. Remarks 17 Rat 31 80 10 2.0 0.86 1.6-2. 4 0.6-1. 2 Immature 22 Rat 26 120 10 2.47 0.86 2.2-33 0. 8-1.0 Immature 23 Rat 4 25 10 2.6 1.1 2 . 5-3 . 0 1.0-1. 4 Immature 31 Duck 4 1 1 4.1 1.5 4.1 1.5 Immature 45 Rat 5 23 10 3.8 1.7 3. 1-4.5 1.4-2. 3 Some mature 47 Duck 3 7 7 6.1 3.0 5. 8-6. 5 2.8-3. 1 All mature 51 Rat 6 8 8 5.4 2.7 4. 7-6. 2 2. 5-2. 9 All mature 56 Duck 2a 17 10 7.9 2.9 7. 1-8.7 2. 7-3.0 All mature 59 Rat 8 23 10 3.9 1.7 3. 4-4. 6 1. 5-2.0 Some mature 70 Rat 15 34 10 4.1 1.7 3. 4-5. 4 1.5-1. 9 All mature 92 Rat 13 28 10 5.0 2.3 4. 2-5. 8 1.7-2. 7 All mature 92 Rat 14 2 2 7.0 3.2 6. 6-7. 5 3. 1-3.3 All mature 193 Rat 18 5 4 8.2 3.0 7. 0-9. 5 2. 8-3. 3 All mature 193 Rat 21 3 3 8.6 3.1 7. 0-9. 5 3. 0-3. 2 All mature 226 Rat 60 4 4 6.0 3.1 5. 5-6. 4 2. 7-3. 4 All mature 238 Rat 52 2 2 7.3 2.9 6. 9-7. 7 2. 5-3. 3 All mature 286 Duck 4a 10 10 6.9 3.54 6. 4-7. 4 3. 2-4.0 All mature 359 Duck la 2 2 7.2 3.75 7. 0-7. 2 3. 5-4.0 All mature 424 Rat 50 1 1 10.5 3.5 10.5 3.5 All mature 507 Duck 5a 5 5 7.4 3.78 6. 5-8.0 3. 5-4. 2 All mature 711 Rat 28 1 1 8.5 4.0 8.5 4.0 All mature 711 Duck 6a 3 3 9.1 4.65 9. 0-9. 2 4. 6-4. 7 All mature Size and Longevity of Z. lunata. As pointed out previously, the size of worms of any given age as well as the rate of development to sexual maturity varies with the number of worms in the host. When many worms of the same age are present, the size varies more and the worms are smaller than when only a few worms of the same age are present. Table 8 shows the average size, range of size, and the number of worms present at various ages from 17 days to 711 days in rat and duck hosts. The relationship between num- ber and size of specimens is illustrated well by the data on rats 13 and 14, both of which on the same day were fed equal numbers of metacer- cariae from the same snail host. Rat 13 harbored 28 worms in the cecum and rat 14 only 2. The Table 8 for rats 6 and 8 killed 51 and 59 days after experimental infestation and yielding 8 and 23 worms respectively shows the same relation- ship. On the other hand worms of the same age occurring in approximately equal numbers in different hosts tend to be more uniform in size. It was observed in ducks that if one cecum con- tained only one worm and the other harbored several, the single worm which occupied a cecum by itself was considerably larger (8.04 mm. X 4.25 mm.) than the other worms averaging 7.2 mm. x 3.6 mm. from the other cecum (Duck 5a). Rankin (1937) also pointed to the relationship between number and size of trematodes within a host and suggested that crowding may be the factor concerned. He stated, “It has been ob- 1941] 83 Willey: The Life History and Bionomics of Zygocotyle lunata served also, that the trematodes Brachycoelium, Plagitura, and Megalodiscus, when present in large numbers, are usually small, though mature. Crowding of many individuals within a small area may account for small size, for when these flukes occur in small numbers, they are much larger. ” The smallest sexually mature Zygocotyle lunata obtained from experimentally infected hosts was 3.1 mm. in length and 1.4 mm. in width, and the largest specimen measured 9.2 mm. X 4.7 mm. The smaller worms were collected from a 45-day infestation in rat 5. From the smaller size the worms continue to grow regularly as they get older; and, as seen in Table 8, rat 50 contained a 424-day-old worm measuring 10.5 mm. X 3.5 mm. The worms obtained after 711 days of growth in rat 28 and in duck 6a are still larger, the largest of the three from the duck being 9.2 mm. in length and 4.7 mm. in width. This represents an increase of many times in volume over the size of the worms when first sexually mature. These worms are larger than any of this species reported heretofore in the literature. The sizes recorded in Table 8 are comparable since the same killing procedure was followed in all cases. The worms were slightly flattened on a large 2x3 inch glass slide under the weight of an ordinary 1x3 inch slide and killed with an aqueous saturated solution of corrosive subli- mate containing 3% of acetic acid. The Table demonstrates that worms when first mature are larger in ducks than they are at a similar stage of development in rats. Ducks 3 and 2a con- tained mature worms 47 and 56 days old respec- tively which are much larger than the newly matured worms from rats 8 and 15 in which the parasites are 59 and 70 days old respectively. Some of the disparity in size is due to the fact that a greater number of worms were present in the rats. In the older worms the difference in size lessens until it disappears altogether in those of 200 days or older from the two host species. In these cases worms of the same age tend to be of the same size regardless of the host in which they developed. Specimens of Zygocotyle lunata may live for more than 2 years in ducks and rats. In the rat, the length of life of Z. lunata is to some extent limited by the life span of the rat. Rat 28 was about 3 months old when fed metacercariae on January 31, 1938. Eggs of Z. lunata were col- lected continuously from the feces and an ex- amination made on January 5, 1940, yielded numerous eggs. By this time, the rat, a male, was becoming quite feeble and slept most of the time. On January 12, 1940, this rat, barely able to walk across the cage, was killed and one large worm was recovered from the cecum 711 days after ingestion of the metacercariae. The rest of the intestine was not examined. The worm was very active and contained many eggs in the uterus. It extruded at least 40 normal-appearing eggs in the dish of water before it was killed and fixed. These eggs were washed and they devel- oped normally, indicating that the old worms are still able to reproduce and would probably live much longer. Duck 6a was also killed 711 days after a single experimental feeding with metacercariae and the 3 worms recovered were the same as the one of the same age from the rat, except that they were slightly larger. Another duck (no. 1) was very disappointing as a subject for longevity records on Zygocotyle. It was given a single feeding of encysted larvae on October 14, 1937 (Table 4), and showed eggs of Zygocotyle in the feces after 41 days and inter- mittently from that time on. After about 18 months of infestation, only a few eggs were obtained in each positive fecal examination but some were collected on October 20 and 26, 1939. Two days later, October 28, the duck was killed but no worms were found. Apparently the in- festation had been lost during the preceding 48 hours. The last eggs had been collected 742 days after infestation and on the 744th day the worms were gone. This does not necessarily indicate, however, that the worms live for only about 2 years. In Z. lunata, the parasites apparently keep on increasing in size as long as they live, at least up to 2 years. It has been shown that many, and in a few cases all, the worms are lost long before this age is attained. Natural infestations in ducks probably carry over from one year to the next just as the experimental infestations in laboratory-raised ducks do. Gower (1938a), in a study of seasonal abundance of the parasites of wild ducks, found Zygocotyle in 12 of 104 ducks examined, with a slightly higher percentage of infestation during the summer and a sudden drop in the autumn. In view of the present data regarding longevity of metacercariae and of adults of Zygocotyle, the significance of Gower’s data on seasonal abundance in this species seems doubtful. The variation reported in numbers of ducks infected at the different seasons: 17.5% in spring, 23% in summer, 4% in fall and 10% in the winter, is probably not significant. The birds may become infected with Z. lunata at any season but probably pick up the cysts less readily in winter when ice serves to lessen the chances for infestation. However, with the relatively long span of life of the parasite, very little difference probably occurs in the incidence of this form at different seasons. Measurements of Z. lunata illustrate the need for caution in attaching much importance to size for specific diagnosis. As in some other trema- todes, extreme variation exists in size of adult specimens. In the experimentally raised and genetically similar material dealt with in the present paper, old mature worms are many times larger in volume than younger, newly-maturecl individuals (Table 8). Measurements for the earlier stages of development are presented in Table 7. Body growth and the growth in size of organs proceed proportionately in a regular progressive manner up to the time of sexual maturity. Miller (1939) reported a decrease in size of developing Postharmostomum laruei in mice during the first 30 hours, and suggested 84 Zoologica: New York Zoological Society that a similar decrease probably occurs in other digenetic flukes upon entering the bodies of their definitive hosts. It is obvious from Table 7 that no such decrease occurs in Zygocotyle. The specimens after 15 hours in the rat are slightly larger than metacercariae, even though they have emerged from their cysts only a short time before. Some metacercariae have not yet ex- cysted after 15 hours. Table 9 presents the comparative measure- [XXVI: 13 to specific diagnosis since trematodes commonly undergo a growth period of this sort prior to maturity. On the basis of the increase in size following sexual maturity, he emphasized the undesirability of placing too much importance on size in specific diagnosis. With reference to his measurements, he says, “The differences in size between different ages of the same fluke, as shown here, are comparable to those which have been used, at times, as a basis for indicating Table 9. Comparative measurements in mm. of stained and cleared specimens of Zygocolyle lunata at different ages. (Averages of several specimens in most cases.) Age in days and host Length Width Ace- tabulum Oral sucker 11— Rat 3 2.14 .825 . 594 X . 548 . 264 X . 264 14 — Duck 4 1.87 .740 . 745 X . 567 .258 X. 258 23— Rat 4 2.60 1.12 1 06 X.878 .396 X. 376 31 — Duck 4 4.10 1.48 1.49 XI. 06 .429 X. 396 45 — Rat 5 3.33 1.28 1 . 06 X . 807 .488 X. 475 (Immature) 45 — Rat 5 3.10 1.70 1.05 X. 825 .462 X . 430 (Mature) 47 — Duck 3 6.10 3 00 1.59 XI. 06 .521 X 462 51 — Rat 6 5.48 2.65 1.30 XI. 06 .613 X.628 92 — Rat 14 7.05 3.20 1.48 XI. 19 . 552 X . 637 193 — Rat 21 8.23 2.97 1.59 XI. 27 . 689 X . 637 359 — Duck la 7.20 3.75 1.48 XI. 48 . 552 X . 552 507 — Duck 5a 7.71 4.07 1.82 XI. 48 . 595 X . 595 711 — Duck 6a 9.10 4.65 1.91 XI. 48 . 660 X . 627 Oral evag- Esophageal Anterior Posterior inations bulb testis testis Ovary .099 X .066 .118 X .092 .118 X .079 .115 X .069 .060 X .046 .085 X .070 .145 X .090 .099 X .066 .099 X .066 .055 X .050 .175 X .112 .231 X .151 .455 X .231 .429 X .264 .132 X . 132 . 198 X .112 .265 X .178 .330 X .198 .297 X .198 .264 X .158 .198 X .118 .218 X .132 .396 X .297 .396 X .363 .119 X .107 .180 X .127 .264 X .190 .660 X .264 .660 X .297 .198 X .132 .205 X .129 .328 X .219 1 .09 X .512 .972 X. .549 .476 X .264 .264 X. .158 .383 X. 208 1.04 X .552 1.04 X, .594 .445 X. .255 .212 X. .170 .382 X .255 .892 X .425 .935 X ,595 .425 X, .297 .243 X. 212 .403 X. .218 1.10 X. .743 1.18 X. 743 .637 X. .254 .212 X .170 .382 X. 245 1.06 X .425 1.06 X. 425 .637 X. ,255' .212 x. 191 .362 X. 232 1.44 X. 595 1.57 X. 637 .722 x. .275 .212 X. 170 .380 X. 255 1.10 X. .510 1.06 X. .552 .637 X. 264 ments of worms varying in age from 11 to 711 days. The measurements are averages of several worms in most cases and are taken from similar- ly stained and cleared whole mounts. It is apparent that size of body and size of the con- tained organs increases proportionately up to sexual maturity. After sexual maturity is at- tained, however, the body organs do not continue to increase in size significantly in proportion to the increase in gross size of the worm as it be- comes older and larger. Some individual varia- tion occurs, but the apparent slight increase in size of some organs, as the acetabulum, does not parallel the rate of increase shown in total body measurements (Figs. 20-25). A comparison of body size and organ size in specimens 47 and 51 days old with those of specimens 92 to 711 days old (Table 9) shows little significant growth in size of organs but a very considerable increase in gross size. Miller (1939) made observations on the rate of growth in Postharmostomum and described an increase in both length and width between worms which are 400 hours old, measuring 3.07 mm. by 1.09 mm., and worms 1,100 hours old which are 3.99 mm. long and 1.32 mm. in width. The worms are apparently sexually mature at 400 hours. He presented no data on size for ages intermediate between 400 and 1,100 hours, and did not report the range of variation among the specimens. The average measurements showing an increase in length and width of the worms during the stages preceding sexual maturity (before 400 hours) are not significant with respect different species.” While this may be true, it should be pointed out that the reported increases in length of 30 per cent., and in width of 17 per cent., following sexual maturity in Postharmo- stomum, are not greater than the variation in size which may occur in different specimens of Zygocotyle of the same age collected from a single host animal. In Zygocotyle, the 70-day-old worms collected from rat 15 (Table 8) varied in length from 3.4 mm. to 5.4 mm., the longer specimens being 58 per cent, greater in length than the smaller ones. Similarly the 92 day old specimens from rat 13 exhibit a 38 per cent, difference. As shown earlier, a wider variation in size of worms occurs in the hosts which harbor a large number of specimens than in those which contain relatively few. In Zygocotyle, worms of a given age are larger when only a few are present than when many have developed to- gether in the same host. The possibility exists that this relationship may be a factor in the size difference between 400 and 1,100 hour worms in Postharmostomum, since 28 flukes of the 400 hour group were present in the host animal, while only 5 were found in the mouse which yielded the larger 1,100 hour worms. In view of the relationships between number, size and age of specimens demonstrated in Zygocotyle, the data given by Miller for Postharmostomum laruei do not justify the conclusions presented by him regarding trematodes in general. During the course of the infestations with Zygocotyle, frequent fecal examinations for eggs of the parasite were conducted. Interesting 1941] Willey: The Life History and Bionomics of Zygocotyle lunata 85 differences appear in the results obtained from feces of rats and ducks. The same procedure was followed in all cases. Fecal samples were broken up in water and strained through a fine wire screen into a settling dish in which the material was then washed several times by the decanting method. The eggs were collected under a binocular dissecting microscope. In every fecal examination of rats infected with mature Zygocotyle, eggs were obtained. Rat 28 was examined more than 50 times over a period approaching two years. The number of eggs collected from 8 fecal pellets varied from 650 in the early months of the infestation to as few as 25 during the last few weeks of the life of the rat. Some were always present. Feces of infected ducks, however, did not always contain eggs. For some reason not clear to the writer, a bird would apparently be negative, and then a week or two later, eggs would again be present. Daily fecal examinations sometimes failed to yield eggs for periods up to 2 weeks, after which eggs would be plentiful again for a similar period in daily collections of feces. Of 78 recorded examinations of fecal samples from duck no. 1, 43 were positive and 35 were negative, but the significant feature is that the feces were often consistently negative or positive for periods of from 8 to 13 successive days. Although a periodicity in egg production for Zygocotyle in ducks is suggested by such data, it apparently does not occur since it certainly does not exist in the rat host. The results cannot be accounted for by loss of worms and subsequent reinfestation, because no opportunity was af- forded for reinfestation. The only explanation that can be offered at present is the element of chance combined with the peculiar action of the ceca in ducks. Fecal samples from other in- fected ducks were similarly negative from time to time for Zygocotyle eggs, although the hosts were unquestionably infected. The data are not sufficiently complete to draw any conclusions other than that failure to find eggs of trematodes living in the ceca of ducks, after only a few fecal examinations, does not necessarily indicate that the bird is not infected. Caution must be exer- cised in using such ducks for feeding experiments in life history studies. The Adult. The morphology of Zygocotyle lunata has been adequately described by Fischoeder (1903), Stunkard (1917), Price (1928) and Gower (1938). Since the tables presented in the present work include comparative measurements and other information concerning variation within the species, no detailed description of the adult is given. Figures 20-25 are photomicrographs of whole mounts at various stages of development, from 5 days to 711 days old, showing the relation between size of organs and size of the body. Figures 23 and 24 illustrate, among other things, the fact that the acetabulum does not increase in size in proportion with increase in size of body as the worms grow older and larger, but is pro- portionately smaller in older than in younger worms. The actual sizes and ages of these specimens is given in the explanations of the figures and the average sizes for the organs appear in Table 9. Stunkard (1917) transferred Amphistoma luna- tum to the genus Zygocotyle and erected a new subfamily, with Zygocotyle as type genus, to contain it. The subfamily Zygocotylinae was first named by Ward (1917). Bhalerao (1931) described a new genus and species, Stunkardia dilymphosa, and placed it with Zygocotyle in the subfamily Zygocotylinae. On the basis of the structure of Stunkardia dilymphosa, Bhalerao found it necessary to modify the definition of the subfamily. He described two pairs of lymph vessels in the new species, as indicated by the specific name, and therefore, in the new diagnosis he includes, “Lymphatic system with a pair of dorsal and a pair of ventral lymph canals.” The lymph system of Zygocotyle, the type genus, had not been described at that time. Willey (1933) showed that Zygocotyle possesses only a single pair of main lymph channels, and pointed out that, “The citation with respect to the lymph system in the subfamily must be modified or else eliminated entirely from the definition.” Furthermore, in view of the report by Price (1928), showing Bos taurus as a host of Zygocotyle, and on the basis of the experimental infestations obtained in a sheep and in rats by the present author, that part of Bhalerao’s diagnosis con- cerning the host relationships of the subfamily Zygocotylinae, “Parasites of birds and reptiles,” must therefore be changed to include parasites of mammals. Although Nasmark (1937) cited the work of Price (1928), showing that Zygocotyle occurs in the cow, supporting the earlier host record by Diesing (1836) of this species from a deer, he apparently did not accept it as valid. He stated (p. 436), “Hitherto known definitely only from ducks in America. A specimen from Bos taurus may be wrongly labelled (?).” The experimental infections in the rat and sheep accomplished in the present work certainly leave no further doubt that Zygocotyle occurs in mammals as well as in birds. In his diagnosis of the subfamily Zygocotylinae, Nasmark (1937) stated (p. 444), “So far as is known with cer- tainty they parasite (sic) only in American ducks.” Nevertheless he cited the work of Bhalerao (1931) who placed Stunkardia dilym- phosa, from a reptile, in the subfamily Zygo- cotylinae. It is not clear whether Nasmark inferred that S. dilymphosa does not belong in the subfamily or whether the statement was made in error. If S. dilymphosa should not be included, as seems likely to the present writer, then Zygocotyle lunata is the only species as yet known in the subfamily Zygocotylinae. Summary. Beginning with cercariae (C. poconensis Willey, 1930) from naturally infected snails of the species Helisoma antrosum, the complete life cycle of Zygocotyle lunata was demonstrated in the laboratory. The cercariae encyst in the open 86 Zoologica: New York Zoological Society [XXVI: 13 and metacercariae fed to laboratory-raised rats, ducks and a sheep developed into adult worms. Eggs collected from feces were embryonated and the miracidia penetrated laboratory-raised Heli- soma antrosum from which cercariae emerged within from 32 to 49 days after exposure. The morphology and activities of the miracidia are described. In the snail the miracidium meta- morphoses into a sporocyst which produces rediae. Some of the rediae contain a single daughter redia at the anterior end as well as cercariae developing at the same time in the same larva. Other rediae contain only young cercariae. It is probable that each redia produces one daughter redia and proceeds from that time on to produce cercariae only. This explains the pres- ence of rediae of all sizes during all stages of the infestation which persists for more than 10 months in the snail. The sporocyst becomes exhausted and disappears soon after the first cercariae are shed. Cercariae leave the redia while still immature and continue their development in the lymph spaces of the snail, after which they emerge and encyst in the open. Encysted metacercariae are infective immediately anti some are still infective when fed to rats after 138 days in the laboratory at room temperature. They will withstand freezing temperatures but are not viable if left out of water for 48 hours at room temperature. No development occurs in the cyst. In the rat the metacercariae excyst in the cecum and develop to maturity. They are normally parasites of the cecum and have been reported from the ceca of various water birds, a deer and a cow. The present experimental in- festations in the rat and sheep constitute new host records for Zygocotyle. Sexual maturity of Z. lunata is attained faster in ducks (41-44 days) than in rats (46-61 days), and the rate of de- velopment is influenced by the number of worms present, more time being required when many worms are present. As the age of the infestation increases, the number of worms is reduced and only a few persist for long after sexual maturity is reached. The host usually eliminates most of them within the first 3 months and retains only 1 to 5 thereafter. An established infestation of Z. lunata in rats and ducks prevents a super- infestation with this species. Size of worms varies with the number present. When many worms of the same age are present, the size varies more and the flukes are smaller than when only a few of the same age are devel- oping together. The data demonstrate the effects of crowding. Z. lunata may live for more than 2 years in rats and ducks, and following sexual maturity the worms continue to increase in size. The smallest sexually mature worm ob- tained experimentally was 3.1 X 1.4 mm. and the largest measured 9.2 X 4.7 mm. when 711 days old. Although gross size increases greatly, the sizes of organs in the body do not increase proportionately. The value of size as a species difference in trematodes is discussed. Regular fecal examinations of ducks infected with Z. lunata often failed to show eggs of the parasites which were resident in the ceca. Feces of in- fected rats always yielded eggs. Ducks should not be considered negative for worms living in the ceca after only a few negative fecal examina- tions. Literature Cited. Ameel, D. J. 1934. Paragonimus, its life history and distribu- tion in North America and its taxonomy (Trematoda; Troglotrematidae). Amer. Jour. Hyg. 19: 279-317, 6 Pis. Barlow, C. H. 1925. The life cycle of the human intestinal fluke Fasciolopsisbuski (Lankester). Amer. Jour. Iiyg., Monographic Series, No. 4: 1-98, 10 Pis. Beaver, P. C. 1929. Studies on the development of Allasso- stoma parvum Stunkard. Jour. Parasitol. 16: 13-23, 1 PI. Bennett, H. J. 1936. The life history of Cotylophoron cotylo- phorum, a trematode from ruminants. 111. Biol. Monogr. 14 (4): 1-119, 9 Pis. Bhalerao, G. D. 1931. Two new trematodes from reptiles: Paryphostomum indicum n. sp. and Stunkardia dilymphosa n. g., n. sp. Parasitol. 23: 99-108. Chandler, A. C. 1937. Studies on the nature of immunity to intestinal helminths. VI. General resu- me and discussion. Amer. Jour. Hyg. 26: 309-321. 1939. The nature and mechanism of immunity in various intestinal nematode infections. Amer. J. Trop. Med. 19: 309-317. Coe, W. R. 1896. Notizen fiber den Bau des Embryos von Distomum hepaticum. Zool. Jahrb., Abt. f. Anal. 9: 561-571, 1 PI. Diesing, K. M. 1836. Monographie der Gattungen Amphistoma und Diplodiscus. Mus. Naturg. 1 : 235-260, 3 Pis. Diesing, K. M. 1850. Systema Helminthum. Vindebonne (1850) 1: 285-477. Dujardin, F. 1845. Histoire Naturelle des Helminthes ou vers intestinaux. 645 p., illus. Paris. (Cited after Price, 1928.) Fischoeder, F. 1903. Paramphistomiden der Saugethiere. Zool. Jahrb., Syst., Geog. und Biol, der Thiere. 17: 485-660, 11 Pis. Gower, W. C. 1938. Studies on the trematode parasites of ducks in Michigan with special reference to the mallard. Agric. Exp. Station, Mich. State Coll., Sect, of Bad. and Zool. Mem. 3: 1-94. 1938a. Seasonal abundance of some parasites of wild ducks. Jour. Wildlife Management 2 (4): 223-232. Hall, M. C. 1927. The parasite problems of the live stock industry in the United States and in Central America. Jour. Amer. Vet. Med. Assoc. (N. S. 23) 70: 935-947. 1941] 87 Willey: The Life History and Bionomics of Zygocotyle lunata Herber, E. C. 1938. On the mother redia of Diplodiscus tem- peratus Stafford, 1905. Jour. Parasitol. 24: 549. Ishii, Y. 1934. Studies on the development of Fasciolop- sis buslci, Parts I— III. Jour. Med. Assoc. Formosa 33: 349-412. Johnson, J. C. 1920. The life cycle of Echinostoma revolutum (Froelich). Univ. Calif. Publ. Zool. 19: 335-388, Pis. 19-25, 1 Text fig. Krull, W. H. and Helen F. Price 1932. Studies on the life history of Diplodiscus iemperatus Stafford from the frog. Occas. Papers Mus. Zool., Univ. Mich. No. 237: 1-41. Krull, W. H. 1934. Life history studies on Cotylophoron cotylophorum (Fischoeder, 1901) Stiles and Goldberger, 1910. Jour. Parasitol. 20: 173-180, 1 Text fig., 1 Table. Le Roux, P. L. 1930. A preliminary communication on the life cycle of Cotylophoron cotylophorum and its pathogenicity for sheep and cattle. 16. Rep. Director Vet. Serv., Dept. Agric. Union South Africa, Pretoria, pp. 243-253, 7 Figs. (Cited after Bennett, 1936.) Looss, A. 1892. Ueber Arnphistomum subclavatum Rud. und seine Entwicklung. Festschr. Leuck- art, Leipzig, 147-167, 2 Pis. 1896. Recherches sur la Faune parasitaire de L’Egypte. Premiere Partie, Memoirs de L’Inslitut egyptien, 3: 1-252, 16 Pis. 1902. Ueber neue und bekannte Trematoden aus Seeschildkroten. Zool. Ja.hrb., Syst. 16: 411-894. Lynch, J. E. 1933. The miracidium of Heronimus chelydrae MacCallum. Quar. Jour. Micros. Sci. 76: 13-33, 2 Pis., 2 Text figs. Manter, H. W. 1926. Some North American fish trematodes. III. Biol. Monogr. 10: 129-264, 6 Pis., 2 Charts, 1 Text fig. Miller, J. N. 1939. Observations on the rate of growth of the trematode Postharmostomum laruei McIn- tosh 1934. Jour. Parasitol. 25: 509-510. Nasmark, K. 1 937. A revision of the trematode family Param- phistomidae. Zool. Bidrag, Uppsala 16: 301-566, 13 Pis., 104 Text figs. Ortmann, W. 1908. Zur Embryonalentwicklung der Echino- rhynchen. Zool. Jahrb. f. Anal. 26: 255- 293, 2 Pis. Price, E. W. 1928. The host relationship of the trematode genus Zygocotyle. Jour. Agric. Research 36 (10): 911-914. Price, Helen F. 1931. Life history of Schistosomatium douthitti (Cort). Amer. Jour. Hyg. 13: 685-727, 4 Pis. Rankin, J. S. 1937. An ecological study of parasites of some North Carolina salamanders. Ecol. Mono- gr. 7: 169-269. Reisinger, E. 1923. Untersuchungen fiber Bau und Funktion des Excretionsapparates digenetischer Trematoden. Zool. Am. 57: 1-20, 5 Text figs. Sinitsin, D. 1931 . Studien fiber die Phylogenie der Tremato- den, IV. Zeit.f. IFm. Zool. 138: 409-456, 15 Text figs. Stoll, N. R. 1929. Studies with the strongyloid nematode, Haemonchus contortus. Amer. Jour. Hyg. 10 (2): 384-418. Stunkard, H. W. 1916. On the anatomy and relationships of some North American trematodes. Jour. Para- sitol. 3: 21-27. 1917. Studies on North American Polystomidae, Aspidogastridae, and Paramphistomidae. III. Biol. Monogr. 3 (3): 287-395, 11 Pis. 1923. Studies on North American blood flukes. Bull. Amer. Mus. Nat. Hist. 48: 165-221, 13 Pis. Suzuki, S. 1931. Researches into the life-history of Fasciola hepalica and its distribution in Formosa. Jour. Med. Assoc. Formosa 30: 1418-1469, 3 Pis., 13 Tables. SziDAT, L. 1936. tjber die Entwicklungsgeschichte und den ersten Zwischenwirt von Par arnphistomum cervi Zeder, 1790 aus dem Magen von Wiederkauern. Zeitschr. f. Parasitenk. 9: 1-19, 14 Text-figs. Takahashi, S. 1928. Ueber die Entwicklungsgeschichte des Par arnphistomum cervi. (Abstract.) Zen- tralbl. f. d. ges. Hyg. Berl. 18: 278. (Cited after Bennett, 1936.) Taliaferro, W, H, 1940. The mechanism of immunity to metazoan parasites. Amer. Jour. Trop. Med. 20: 169-182. Thomas, A. P. 1883. The life history of the liver fluke ( Fasciola ; hepalica). Quar. Jour. Microsc. Sci. 23: 99-133, 2 Pis. Ward, H. B. 1917. On the structure and classification of North American parasitic worms. Jour. Parasitol. 4: 1-12. Willey, C. H. 1930. An amphistome cercaria, C. poconensis, with branched main excretory tubes. Anat. Rec. 47: 364 (Abstract). 1933. The lymph system of Zygocotyle lunata (Trematoda, Paramphistomidae). Para- sitol. 25: 242-247. 1936. The morphology of the amphistome cercaria, C. poconensis Willey, 1930, from the snail, Helisoma antrosum. Jour. Para- sitol. 22 (1): 68-75. 1937. The development of Zygocotyle from Cercaria poconensis Willey, 1930. Jour. Parasitol. 23 (6): 571 (Abstract). 1938. The life history of Zygocotyle lunata. Jour. Parasitol. 24 (6) suppl.: 30 (Abstract). 88 [XXVI: 13 Zoologica: New York Zoological Society EXPLANATION OF THE PLATES. Plate I. Photomicrographs of eggs and miracidia of Zygocotyle lunata. Fig. 1. Egg, living, from feces. Length, 0.145 mm. Fig. 2. Eggs, showing variation in shape and size. Fig. 3. Embryo after 13 days of development. Fig. 4. Embryo after 18 days of development. Fig. 5. Embryo after 21 days of development. Fig. 6. Miracidium, living, slightly flattened under a coverglass. Length, 0.210 mm. Fig. 7. Miracidium, whole mount of silver impreg- nated specimen, showing entire thickness. Length, 0.191 mm. Fig. 8. The same miracidium as in figure 7, with higher initial magnification showing critical focus on the upper surface. Length, 0.191 mm. Plate II. Free-hand drawings of some larval stages of Zygocotyle lunata. Abbreviations. ap, apical papilla br, dorsal nerve mass ce, cercaria ci, cilia cn, epidermal cell nucleus dr, daughter redia ed, excretory collecting duct ep, excretory pore es, eye-spots fl, flame cell gb, germ ball gc, germ cell gn, ‘gut’ nucleus in, intestine pg, ‘primitive gut’ ph, pharynx re. redia sc, subepithelial cell nucleus sp, aperature for sensory papilla Tl, Epidermal cell of 1st tier T2, Epidermal cell of 2nd tier T3, Epidermal cell of 3rd tier T4, Epidermal cell of 4th tier ve, vesicle Fig. 9. Miracidium from dorsal aspect; reconstruc- tion from observations on numerous living and fixed specimens. Average length, 0.195 mm. Fig. 10. Reconstruction of sporocyst from sections of experimentally infected Helisoma anlro- sum, 28 days after penetration of the miracidium. Length, 0.305 mm. Fig. 11. Young redia containing single, large daughter redia, from living specimen. Length, 0.330 mm. Fig. 12. Older redia containing single young daugh- ter redia and several developing cercariae; 25 days after penetration of the miracidium, , living specimen. Length, 0.860 mm. Fig. 13. Redia, containing active, older daughter redia which is ready to emerge, and several developing cercariae; from living specimen in snail crushed 47 days after penetration of the miracidium. Length, 0.792 mm. Plate III. Photomicrographs of various stages in the life history of Zygocotyle lunata. Fig. 14. Section of sporocyst reconstructed in fig. 10. Note pharynges of 2 rediae and portions of intestine of 2 others. Fig. 15. Redia, living, containing developing cer- cariae and germ balls. Length, 0.775 mm. Fig. 16. Ventral aspect of mature cercaria, living, under medium pressure of coverglass. The tail is still attached but out of focus. Note branched excretory collecting ducts as out- lined by excretory concretions. Length, 0.990 mm. Fig. 17. Whole mount of fixed and stained cercaria from ventral side, killed under slight pressure. Length, 0.660 mm. Fig. 18. Encysted metacercariae attached to the surface of the shell of a snail. Average diameter, 0.289 mm. Fig. 19. Ventral aspect of whole mount of a 10-day old metacercaria dissected from its cyst. Length of specimen, fixed and stained, 0.489 mm. Fig. 20. Ventral aspect of young immature adult after 5 days of development in rat 1. Length, 0.924 mm. Plate IV. Photomicrographs of whole mounts of fixed and stained specimens of Zygocotyle lunata at various stages of development in the final host. Fig. 21. Ventral aspect, after 11 days in rat 3. Length, 2.21 mm. Fig. 22. Ventral aspect, after 14 days in duck 4. Length, 2.12 mm. Fig. 23. Ventral aspect, after 23 days in rat 4. Length, 3.04 mm. Fig. 24. Ventral aspect, after 51 days in rat 6. Length, 6.07 mm. Fig. 25. Dorsal aspect, after 711 days in duck 6a, photographed by reflected light. Length, 9.0 mm. WILLEY. PLATE I ZYGOCOTYLE LUNATA WILLEY. PLATE II. ZYGOCOTYLE LUNATA 20 WILLEY. PLATE III. ZYGOCOTYLE LUNATA. WILLEY. PLATE IV cr ; ZYGOCOTYLE LUNATA. 1941] Beebe & Tee-Van: Lancelets and Hag-fishes 89 14. Eastern Pacific Expeditions of the New York Zoological Society. XXIV. Fishes from the Tropical Eastern Pacific. [From Cedros Island, Lower California, South to the Galapagos Islands and Northern Peru.] Part 1. Lancelets and Hag-fishes.1 William Beebe & John Tee-Van Department of Tropical Research, New York Zoological Society. (Text-figures 1 & 2). [This is the twenty-fourth of a series of papers dealing with the collections of the Eastern Pacific Expeditions of the New York Zoological Society made under the direction of Dr. William Beebe. The present paper is concerned with specimens taken on the Templeton Crocker Expedition (1936), and the Eastern Pacific Zaca Expedition (1937-1938). For data on localities, dates, dredges, etc., of these two expeditions, refer to Zoologica, 22:33-46 (Templeton Crocker) and Zoologica, 23: 278-298 (Eastern Pacific Zaca).} This series of papers on fishes and fish-like animals will list the species known from the region ; those represented by specimens taken on our own expeditions will be treated more ex- tensively. As far as the unrepresented forms are concerned, field characters, size, original and re- gional references, and whenever possible an illustration, are given for each species. Class Leptocardii. Order Cirrostomi. Family Branchiostomidae. Branchiostoma Costa, 1834. Key to Tropical Eastern Pacific Species. la. 68 to 74 myotomes (California to Panama). calif orniense. lb. 78 to 81 myotomes (Peru, Chile and the Gala- pagos Islands (Albemarle)) elongatum. Branchiostoma californiense Andrews. 1 Contribution No. 621, Department of Tropical Re- search, New York Zoological Society. Range: Monterey Bay, California, to Chame Point, Panama, in sand from depths of one foot to thirty-five fathoms. (Mexico: San Luis Gonzales Bay and Arena Bank, Gulf of Cali- fornia, Cape San Lucas; Nicaragua: Corinto; Costa Rica: Piedra Blanca Bay and Gulf of Dulce; Panama: Chame Point.) Description: Dorsal ray-chambers 312 to 374 (average 337); preanal chambers about 50; higher dorsal chambers five to eight times as high as long; dorsal fin one-fifth to one-eighth as high as body; anus located far behind middle of lower lobe of caudal fin; distance from atriopore to origin of lower caudal lobe contained from .8 to 2 times in distance thence to anus; preatri- oporal length 2.65 to 3.3 times the postatrioporal length; myotome formula 43 to 48 + 16 to 19 +8 to 10 = 68 to 74; gonad pouches 27 to 36 (average 33); distance from tip of rostral fin to anal sphincter 13.8 to 16.3 times in total length. (Description from Hubbs, 1922; as our specimens are immature. Illustration from specimen 25,482a, 29.4 mm.) Color: Creamy white ; several of our specimens showed a conspicuous brown band across the center of the snout. Size: Mature specimens 58 to 83.5 mm., our immature individuals were 17 to 48.8 mm. Local Distribution: Our specimens were dredged in sand beneath depths of water ranging from 12 inches to 210 feet. This latter record of 35 fathoms on Arena Bank is the deepest known, 6.5 fathoms being the deepest hitherto recorded. Abundance: The nine specimens were dredged in four widely separated localities. The species is doubtless to be found in all suitable localities throughout the range under discussion. Food: A dark area in the intestine of an 90 [XXVI: 14 Zoologica: New York Zoological Society Amphioxus from the Gulf of Dulce, Costa Rica, resolved into a mass of diatoms of several species. Breeding: All of our specimens are immature; they present, however, the recognizable charac- ters of calif orniense. The 48.8 mm. individual from 35 fathoms had 358 dorsal ray-chambers and was quite free of gonads, while its 37 mm. companion from the same haul showed 31 gonads. Study Material: 9 specimens. Mexico: Arena Bank, Lower California, Station 136:D-30, 35 fathoms, 4 (25,482), 20 to 48.8 mm., May 1, 1936, dredged; Nicaragua: Corinto Harbor, Station 200:D-22, 1.5 fathoms, 2 (27,700), 17 and 24 mm., Jan. 7, 1938; Costa Rica: Piedra Blanca, Station 218:D-2, 5 fathoms, 2 (28,211) 19 and 30 mm., Feb. 5, 1938, dredged; Golfito, Gulf of Dulce, 12 inches deep, 1 (28,649), 36 mm., March 6, 1938, sifted from sand in shallow tidal stream. References: Branchiostoma sp., Cooper, J. G., in Cronise, T. F., Natural Wealth of California, 1868: 498 (First mention of a branchiostomid on Pacific Coast). Branchiostoma lanceolatum., Lockington, W. N., Proc. Acad. Nat. Sci., Phila., 1881 (1882): 114 (Angeles Bay, Lower California). Pellegrin, J., Bull. Mus. Hist. Nat. Paris, 7, 1901: 163, 167 (Several specimens 55-65 mm., from Los Angeles Bay, Lower California). Branchiostoma calif orniense, Andrews, E. A., Studies Biol. Laboratory Johns Hopkins Univers., 5, 1893: 238 (San Diego, California). Jordan, D. S. & Evermann, B. W., Fishes North and Middle America, 1, 1896: 4 (San Luis Gonzales Bay, Gulf of California). Hubbs, C. L., Occ. Pap. Mus. Zool., Univ. Michigan, 105, 1922: 11 (rede- scription of species). Meek, S. E. & Hildebrand, S. F., Marine Fishes of Panama, 1, 1923: 28 (Range extended to Chame Point, Panama; 61 specimens 20 to 37 mm., “tentatively referred to this species in the absence of comparative material”). Ulrey, A. B., Journ. Pan-Pac. Res. Inst., 4 (4) 1929: 2 (Cape San Lucas, Gulf of California) . Discussion: The California Amphioxus, Bran- chiostoma calif or niense, presents an interesting comparison with three species of the western Atlantic, virginiae, floridae and caribaeum. Its maximum length is one-third (34%) greater than the average of the other three. It shows a decided increase in four categories of metameral characters: dorsal ray chambers 16%, preanal chambers 25%, myotomes 18% and gonads 24%. That this is not wholly the result of a larger organism in general (55 as compared with 83.5 mm. in maximum length) is proved by a corre- sponding comparison of the three Atlantic species with elongatum, which replaces californi- ense from the GaMpagos to Chili. The percent- age of the maximum length of this more southern form is only 20% over the Atlantic species, but in preanal ray-chambers it is 46% numerically superior, in myotomes 27%, while it possesses 32% more gonads than the Atlantic species. Branchiostoma elongatum (Sundevall). Range: Peru (Chincha Islands), Chile and the Galapagos Islands (Albemarle). Description: Dorsal ray-chambers numerous, but not accurately countable, and moderately high; preanal chambers about 65 to 75, much more numerous than in other species of Branchio- stoma; anus located slightly in advance of middle of lower caudal lobe; distance of atriopore to origin of this fin lobe contained 1.3 times in total distance behind this point. Preatrioporal length 2.4 to 2.6 times the postatrioporal length; myotomes very oblique; the formula 48 to 51 + 18 + 12 or 13 = 79 to 81. Gonad pouches 37; oral hood reduced in size, as in B. calif orniense. (Hubbs, 1922: 13.) Study Material: None. References: Amphioxus elongatus, Sundevall, C. J., Oefvers. Vet. Akad. Forh., 9, 1852: 147 (description; type locality, Chincha Islands, Peru). Kirkaldy, J. W., Quart. Journ. Microsc. Sci., 37, 1895: 303. Branchiostoma elongatum, Sundevall, C. J., Oefvers. Vet. Akad. Forh., 10, 1853: 12 (Chincha Islands, Peru). Steindachner, F., Fauna Chilen- sis, 1898: 334 (Cavancha Bay, Iquique, Chile). Herdman, W. A., Cambridge Nat. Hist., 7, 1904: 137 (Myotomes 49-18-12, Peru). Snodgrass, R. E. & Heller, E., Proc. Wash. Acad. Sci., 6, 1905: 342 (Galapagos Islands, 13 specimens, the largest 20 mm.). Goldschmidt, R., Zool. Anz., 29, 1905: 132-133 (Peru). Hubbs, C. L., Occ. Pap. Mus. Zool., IJniv. Mich., 105, 1922: 13 (diagnosis). Class Cyclostomi. Order Hyperotreta. Family Myxinidae. Myxine Linnaeus, 1758. Myxine circifrons Garman . Range: Gulf of Panama; known from 20 miles W. X S. of Caracoles Point, in 730 fathoms. Field Characters: Eel-shaped eyeless animals with a series of barbels about the mouth. Upper teeth 13 on each side, lower teeth 11 on each side, of which the anterior three of each upper and the anterior two of each lower series are confluent. 1941] Beebe & Tee-Van: Lancelets and Hag-fishes 91 Color uniform black; head lighter anteriorly. (Illustration after Garman, 1899; 470 mm.) Size: Grows to ISff inches. Study Material: None. References: Myxine circifrons, Mem. Mus. Comp. Zool., 24, 1899: 344, Plate 68, figs. 1-4 (original description, color, figures of entire animal, head, heart and gills; type-locality, Albatross station 2395, 7° 30' 36" N., 78° 39' W., Gulf of Panama in 730 fathoms. Type in Mus. Comp. Zool.). 1941] Beebe & Tee-Van: Sharks 93 15. Eastern Pacific Expeditions of the New York Zoological Society. XXY. Fishes from the Tropical Eastern Pacific. [From Cedros Island, Lower California, South to the Galapagos Islands and Northern Peru.] Part 2. Sharks.1 William Beebe & John Tee-Van. Department of Tropical Research, New York Zoological Society. (Plates I & II; Text-figures 1-34). [This is the twenty-fifth of a series of papers dealing with the collections of the Eastern Pacific Expeditions of the New York Zoological Society made under the direction of Dr. William Beebe. The present paper is concerned with specimens taken on the Noma Expedition (1923), the Arcturus Oceanographic Expedition (1925), the Antares Expedition (1933), the Templeton Crocker Expedition (1936) and the Eastern Pacific Zaca Expedition (1937-1938). For data on localities, dates, dredges, nets, etc., of the second, fourth and fifth of these expeditions, refer to Zoologica, Vol. 8, No. 1, pp. 1-45 ( Arcturus ); Zoologica, Vol. 22, No. 2, pp. 33-46 (Templeton Crocker), and Zoologica, Vol. 23, No. 14, pp. 278-298 (Eastern Pacific Zaca).) Contents. Introduction . . 94 Key to Families of Sharks cf the Tropical Eastern Pacific 94 Superclass Pisces- Class Chondropterygia (elasmobranch fishes). Subclass Plagiostomia (sharks and rays). Superorder Antacea (sharks). Order Hexanchea. Family Chlamydoselachidae 96 Family Hexanchidae 96 Order Galea Suborder Isurida Superfamily Orectoloboidea Family Orectolobidae 96 Ginglymostoma cirratum 96 • Contribution No. 622, Department of Tropical Re- search, New York Zoological Society. 2 The general arrangement adopted here is that of E. Grace White (Bull. Amer. Mus. Nat. Hist., 74 (2), 1937: 36-38). Family Rhineodontidae 97 Rhineodon typus 97 Superfamily Isuroidea Family Alopiidae 97 Family Isuridae 98 Family Cetorbinidae 98 Cetorhinus maximus 98 Suborder Galeorhinida Superfamily Scylliorhinoidea Family Scylliorhinidae 99 Prisliurus xaniurus 99 Ccphaloscyllium uter 99 Cephalurus ccphalus 100 Superfamily Galeorhinoidea Family Triakidae 100 Triakis semifasciata 100 Triakis maculata 101 Triaenodon obcsus. 101 Family Mustelidae 102 Mustelus californicus 102 Muslelus dorsalis 103 Mustelus lunulatus 103 Family Galeorhinidae . 104 Prionace glauca 104 Aprionodon fronto 105 Eulamia aethalorus 106 Eulamia velox 108 Eulamia cerdale 109 Eulamia azureus 109 Eulamia lamiella 110 Eulamia platyrhynclius Ill Eulamia galapagensis 112 Scoliodon longurio 112 Galeocerdo arcticus 113 Galeorhinus sp 114 Family Sphyrnidae 114 Sphyrna zygaena 114 Sphyrna tudes. 115 Sphyrna corona 115 Sphyrna vesperlina 116 Sphyrna media 116 Order Heterodontea Suborder Heterodontida Family Heterodontidae 117 Heterodontus francisci 117 Heterodontus quoyi 117 Order Squalea Suborder Squalida 94 Zoological New York Zoological Society [XXVI: 15 Superfamily Squaloidea Family Squalidae 120 Centroscyllium nigrum 120 Squalus sp 121 Family Scymnorhinidae 121 Isistius brasiliensis 121 Suborder Squatinida. Superfamily Squatinoidea Family Squatinidae 121 Squalina californica 121 Introduction. This paper deals with sharks collected in tropical eastern Pacific waters on five expeditions of the Department of Tropical Research of the New York Zoological Society under the direction of Dr. William Beebe. As an aid to future students we have included all species that have been recorded from the eastern tropical Pacific. The geographical boundaries of the region under consideration in this paper and which we call the “tropical eastern Pacific” are as follows: The coastal waters of North and South America from Cedros Island off the west coast of Lower California, and the Gulf of California, southward to northern Peru, including off-shore islands such as the Galapagos and Revillagigedo groups, and Clipperton, Cocos and Malpelo Islands. As far as references are concerned, we have listed the original reference with the type locality, and references referring to the region under dis- cussion. Additional references have been added, however, whenever their inclusion was felt neces- sary. Some of the more commonly cited papers have been referred to by name and not by publi- cation, serial and page numbers; the full refer- ences will be found on page 122. Synonyms of nominal forms described from the region are included, but not necessarily those from extra- limital localities. Thirty-three sharks are reported from the waters of the tropical eastern Pacific as delimited. As might be expected, most of these species are forms that live dominantly in warm wafers. But surprisingly enough a number of species usually found widely distributed in warm waters of other parts of the world and that might be expected to be in our region, are unreported from the area under consideration. Whether this absence is an actual one, or udiether it is the result of compara- tively few collections having been made in the region, is a question. Under any circumstances these sharks must be uncommon as there have been a sufficient number of collections made in the region to have produced at least one speci- men of these species. We are indebted to Dr. Leonard P. Schultz of the U. S. National Museum, Mr. John T. Nichols of the American Museum of Natural History, Prof. Albert E. Parr of the Peabody Museum, Yale University, and Dr. H. B. Bigelow and Mr. William C. Schroeder of the Museum of Com- parative Zoology, Cambridge, for the loan of material and for valuable information; to Miss Janet Wilson for inking the outline drawings and to Miss Jocelyn Crane and Mr. Tosliio Asaeda for photographs. Key to the Families of Sharks of the Tropical Eastern Pacific3 1. Body not markedly depressed or expanded laterally, except in the case of the hammer- head sharks, where the head only is expanded 2 Body depressed, usually widely expanded laterally 16 2. Gill-openings 6 or 7 on each side, a single dorsal fin. 3 Gill-openings 5 on each side, two dorsal fins . . 4 3. Body greatly elongate, almost eel-shaped; mouth anterior .... Chlamydoselachidae, p. 96 Body moderately elongate; mouth inferior Hexanchidae, p. 96 4. Anal fin present 5 Anal fin absent 15 5. Dorsal fins provided with a strong spine anteriorly Heterodontidae, p. 117 Dorsal fins without spines anteriorly 6 6. First dorsal fin over or behind the pelvic fins . . 7 First dorsal fin in advance of the pelvic fins. . 8 7. Nostrils confluent with the mouth; tail directed upward somewhat from the body Oredolobidae, p. 96 Nostrils not confluent with the mouth; tail not directed upward from the body Scylliorhinidae, p. 99 8. Caudal peduncle with a keel on each side; caudal fin lunate 13 Caudal peduncle without a keel on each side; caudal fin not lunate, its upper lobe two or more times the length of the lower 9 9. Tail exceedingly long, forming about one-half of the total length; eyes without nictitating membranes or folds Alopiidae, p. 97 Tail moderately developed, forming less than one-third the total length; eyes with nicti- tating membranes or folds 10 10. Head hammer- or kidney-shaped, its sides ex- tended laterally Sphyrnidae, p. 114 Head normally formed, without lateral exten- sions 11 11. More than two rows of teeth in use; teeth in bands or pavement 12 One or two rows of teeth in use; teeth com- pressed, triangular, not in bands or pavement Galeorhinidae, p. 104 12. Teeth pavement-like, the cusps flattened Mustelidae, p. 102 Teeth not pavement-like, each tooth with three to five sharp cusps Triakidae, p. 100 13. Last gill-opening entirely in front of the pectoral fins 14 Last gill-opening above the base of the pectoral fins; size enormous Rhineodontidae, p. 97 14. Gill-openings very large, extending from the back and nearly meeting under the throat; teeth very small; size enormous Cetorhinidae, p. 98 Gill-openings moderate, not as above; teeth very large and sharp Isuridae, p. 98 3 In addition to the families found in the eastern tropical Pacific, a few other families have been included that have representatives immediately north and south of the province here treated. These have been inserted on the presumption that they might be found sometime within the area The keys in this paper are based only upon the species that are found within the area under consideration; they will not necessarily be found to apply to sharks of the same genera in other parts of the world. 1941] Beebe & Tee-Van: Sharks 95 SAN LUCAS B. CLARION ISL. BANDERAS BA CHAMELA B.\ TENACATITA B. MANZANILLO- SIHUATANEJO” ACAPULCO" __ DULCE R> PORT ANGELES"^ PORT GUATULCO- SANTA CRUZ B.'' TANGOLA-TANGOLA B. 1 GULF OF FnNAFrA-' GULF OF (alcat.ai ,sl. SAN JUAN DELSURr* PORT PARKER MU RC I EL AGO B. POTRERO GRANDE PORT CULEBRA BRAXILITO B. PIEDRA BLANCA B NICOYA GULF OF DULCE EASTERN PACI F1C E X P E D T 1 0 N S NEW YORK ZOOLOG ICAL SOCIETY S H 0 R E C OLLECTI NG STATIONS GA L APAGOS IS. Text-figure 1. Principal localities in the tropical eastern Pacific where collections were made by the Department of Tropical Research of the New York Zoological Society. 15. Dorsal fins each provided with a spine Squalidae, p. 120 Dorsal fins without spines Scymnorhinidae, p. 121 16. Gill-openings on sides of body; anterior exten- sion of the pectoral fins separated from the neck by a deep notch in which lie the gill- openings Squatinidae,p. 121 Gill-openings on under side of the body. (Rays and mantas; these will be treated in a suc- ceeding paper.) 96 [XXVI: 15 Zoologica: Neiv York Zoological Society Systematic Account. Family Chlamydoselachidae. Chlamydoselachus Garman, 1884. Chlamydoselachus anguineus Garman. Unrecorded from our region, although Garman4 mentions the following: “This shark is one that may confidently be expected to appear in future collections from the region about the Gahipagos.” Family Hexanchjdae. Hexanchus Rafinesque, 1810. Hexanchus griseus, the six-gilled shark, is one of a number of sharks unrecorded from the tropi- cal eastern Pacific, but reported from immedi- ately north and south of the region under con- sideration. On the Pacific coast the range is from San Diego, California, northward, and the species is known from Chile, if the synonymizing of the South American form with the northern is correct. Heptranchias Rafinesque, 1810. The seven-gilled sharks also have representa- tives both north and south of the region from Cedros Island to northern Peru. Family Orectolobidae. Gin gly mo stoma Muller & Henle, 1837. Ginglymostoma cirratum (Gmelin). Nurse Shark (Sand Shark; Gato). Range: In our province from the Gulf of Cali- fornia, south to Ecuador. (Mexico: Gulf of California, Mazatlan, Jalisco, Chamela Bay, Manzanillo; Costa Rica: Port Parker, Potrero Grande, Gulf of Nicoya; Panama: Bahia Honda, Panama Bay; Ecuador: St. Helene Bay.) Field Characters: A sluggish, blunt-headed shark with very small eyes; mouth transverse and near the tip of the snout, furnished with a pair of barbels; two large dorsal fins placed far back, the first over the pelvics; the fourth and fifth gill-slits very close together. Olive brown; young covered with small black spots which usually disappear in the adult. (Illustration after Garman; 365 mm.) 4 Garman, S., Mem. Mus Comp. Zool., 24, 1899: 41. No detailed comparison has been made at first hand between nurse sharks from the Atlantic and from the Pacific, and though probably there is specific differentiation, we can consider them at present as only a single species. Size: Reaches a length of 10 feet. Local Distribution: Feeding and usually living close to the bottom in shallow water near shore. Abundance: Cannot be considered a rare shark wherever it is found. Food: A 385 mm. shark taken from a tide pool in Costa Rica had eaten two carideans and five small fishes. One of the latter was a Rupiscartes atlanticus (85 mm.) and another an Anchoviella (43 mm.). An adult shark had eaten a six-inch fish. Enemies: Man was the only enemy of this shark which came to our notice. A dozen nurse sharks, six to eight feet in length, were found on the beach at a camp devoted to drying shark fins, near the tip of Lower California, on May 1, 1936. Unlike the other three species found at this camp, the nurse sharks had their fins intact, these hav- ing evidently no commercial value. Parasites: Two leeches, Pontobdella muricata, were taken from a nurse shark. Breeding: The largest specimen (2,800 mm.) showed no signs of active breeding; the smallest (295 mm.) was taken in a tide pool at Bahia Honda, Panama, on March 19, 1938. Study Material: We observed this shark seven times; three specimens were collected, the others were watched through helmet or water-glass. Mexico: Chamela Bay, 1, observed, ca. six feet, Nov. 10, 1937; Manzanillo Bay, 1 (26,093) 392 mm., Jan. 10, 1938, poisoned; Costa Rica: Port Parker, 1, ca. four feet, Jan. 13, 1938, observed; Potrero Grande, 1, ca. seven feet, Jan. 23, 1938, observed in 2 feet of water; Gulf of Nicoya, (26,170) 2,880 mm., Feb. 23, 1938, snagged through dorsal with hook from Zaca; Panama: Bahia Honda, 1, (26,206) 295 mm., March 19, 1938, poisoned in tidepool; Bahia Honda, 1, ca. 300 mm., March 19, 1938, specimen lost, from same pool as 26,206. References: Squalus cirratus, Bonnaterre, Tabl. encyc. meth., Ichtliy., 1788: 7 (original descrip- tion) . Ginglymostoma cirratum , Jordan, D. S. & Gilbert, C. H., Bull. U. S. Fish Comm., 2, 1882: 105 (Mazatlan, Mexico). Jordan, D. S. & Gilbert, C. H., Proc. U. S. Nat. Mus., 5, 1883: 371 (First record from Pacific coast, 2 ten-inch specimens collected by Xantus, Colima, Mexico). Jordan, D. S. & Gilbert, C. H., Proc. U. S. Nat. Mus., 5, 1883: 620 (Panama). Vaillant, L. L., Bull. Soc. Philom., Paris, (8) 6, 1894: (Gulf of California). Jordan, D. S., Fishes of Sinaloa, 1895: 381, (color, common name “Gata,” 3 specimens, 2 to 6 feet). Jordan, D. S. & Ever- mann, B. W., Fishes North and Middle America, 1, 1896: 26 (short description). Boulenger, G. A., Boll. Mus. Torino, 13, 1898: 1 (Ecuador). Gilbert, C. H. & Starks, E. C., Fishes Panama 1941] Beebe & Tee-Van: Sharks 97 Bay, 1904: 5 (color, Panama). Garman, S., Bull. Mus. Comp. Zool., 46, 1906: 229 (Panama). Regan, C. T., Proc. Zool. Soc. London , 1908: 350 (synonymy, description, Jalisco, Mexico). Garman, S., The Plagiostomia, 1913: 54, plate 7 (description, figures). Meek, S. E., & Hilde- brand, S. F., Marine Fishes of Panama, 1, 1923: 29 (Panama, description). Ginglymostoma fulvum, Jordan, D. S., Proc. U. S. Nat. Mus., 8, 1886: 363 (listed as a doubtful species) . Family Rhineodontidae. Rhincodort Smith, 1849. (Usually consid- ered as a misprint for Rhineodon.) Rhineodoti typus Smith. Whale Shark. (Plate 1, Figs. 1 & 2). Text-figure 3. Range: Warm waters of the Atlantic, Pacific and Indian Oceans. In the eastern tropical Pacific it is known from the following localities, Mexico: Gulf of California, Cape San Lucas, Acapulco; Panama: Panama Bay, Galapagos Islands; Peru: Callao. Field Characters: A giant whale-like shark with spotted head and with the body covered with longitudinal and transverse pale bands forming a checker-board ; each space in the checker-board with a pale yellowish spot. (Illustration after Norman, 1937.) Size: Grows to 45 feet long, with possible records ranging up to 70 feet. General Habits: Considering its size, this is a common fish in Gulf of California waters. Our observations on the species are summarized in “Zaca Venture,” pages 162-170. Study Materials: No specimens. Many obser- vations and photographs were made of this species in the Gulf of California. References: Rhineodon typus, Smith, A., Zool. Journal, London, 16, 1829: 443-444 (original description; type locality, Table Bay, Cape of Good Hope, South Africa). Micristodus punctatus, Gill, T. N., Proc. Acad. Nat. Sci., Phila., 17, 1865: 177. Gill, T. N., Science, 15, 1902: 824-826. Jordan, D. S. & Evermann, B. W., Fishes North and Middle America, 1, 1896: 52 (Quotes original description of teeth). Mowbray, L. L., Preliminary Report on the Taking of the Pacific Whale Shark during the Scientific Cruise of the Yacht “Nourmahal” in the North Pacific, 1933, under the direction of Vincent Astor, Privately printed, July, 1933, No. 1, 2 pp. (Galapagos Islands). Rhineodon typicus, Smith, R. W., Illustrations Zool. South Africa, 1849: Plate 26. Nation, W. S., “South Pacific Times,” Callao, Peru, Jan. 24, 1878. (Callao, Peru). Chierchia, G., Collezioni per Studi di Scienze Naturali Fatte nel Viaggio Intorno al Mondo della R. Corvetta “Vettor Pisani” . . . Anni 1882-83-84-85. Roma, 1885: 66-68 (Panama Bay). Grey, Z., Santa Catalina Islander, May 27, 1925: 10 (Cape San Lucas). Grey, Z., “Fishing Virgin Seas,” New York, 1925: 204-216 (Cape San Lucas). Beebe, W., “The Arcturus Adventure,” New York, 1926: 414 (Galapagos Islands). Gudger, E. W., Science, 65, 1927: 545 (Galapagos Islands). Gudger, E. W., Science, 65, 1927: 211-212 (Gulf of California). Gudger, E. W., Nature, 132, 1933: 569 (Galapagos Islands). Lonnberg, E., Fauna och Flora Upsala, 1933: 97-104 (Acapulco, Mexico). Gudger, E. W., Proc. Zool. Soc. London, 1934: 874-878 (Distribution in the eastern tropical Pacific). Gudger, E. W., Natural History, 36, 1935: 128-132 (Acapulco, Mexico). Gudger, E. W. & Smith, R. S., Bull. N. Y. Zool. Soc., 68—71 (six specimens at Acapul- co, Mexico, photographs). Beebe, W., Bull. N. Y. Zool. Soc., 39, 1936: 241-242 (notes, photo- graphs), (Gulf of California, Cape San Lucas). Gudger, E. W., Nature, 141, 1938: 516 (Panama). Gudger, E. W., California Fish and Game, 24, 1938: 420-421 (Lower California). Fowler, H. W., Acad. Nat. Sci. Phila., Monograph 2, 1928: 248 (Galapagos Islands, check-list). Beebe, W., “Zaca Venture,” New York, 1938: 162-170 (observations and harpooning, abundance, size, Gulf of California and Cape San Lucas). Family Alopiidae. Alopias Rafinesque, 1810. Alopias vulpinus (Bonnaterre). The thresher-shark, although supposedly world-wide in distribution, is unrecorded from our area, but it has been found in considerable numbers in southern California and in Chile. Walford, in writing of southern California Alopias vulpinus, states: “It has been recorded on our coasts as far north as Coos Bay, Oregon, and is said to extend at least as far south as the Isthmus of Panama.” This statement seems to be the only recorded reference to the species in coastal tropical eastern Pacific waters. Alopecias barrae Philippi6 and A. longimana Philippi,6 both reported from Chile, are con- sidered by Fowler7 as being the same as Alopias vulpinus. 6 Philippi, R. A., Anales Univers. Chile, 71, 1887: 553, pi. 5, fig. 2. « Philippi, R. A., Anales Univers. Chile, 109, 1901: 308. 7 Fowler, H. W , Proc. hth Pac. Sci. Congr., Java 1929, Biol. Pap. 3, 1930: 488. 98 [XXVI : 15 Zoologica: New York Zoological Society Whitley8 * points out that the assumption that Alopias vulpinus has a world-wide distribution may not be correct. A number of new forms of Alopias have been described, and the eastern tropical Pacific form may very well represent another species. Family Isuridae. Key to genera mentioned in this paper. la. Teeth slender and sharp, with entire edges. I surus lb. Teeth compressed and triangular, with serrated edges Carcharodon Isurus Rafinesque, 1810. la. Teeth with a basal cusp on each side nasus lb. Teeth without basal cusps, long, flexible and acute glaucus Isurus nasus (Bonnaterre) and Isurus glaucus (Muller & Henle). The genus Isurus and the species mentioned above are unreported from our province, al- though they are present north and south of the area if the Chilean Lamna hudobroii 9 is the same as Isurus glaucus as Fowler states,10 and if Lamna philippi Perez11 is the same as Isurus nasus, as Fowler mentions in the same publication. We have the jaws of an Isurus obtained from a native in the Gulf of Dulce, Costa Rica. There is no definite locality record for this jaw, and although it was probably taken from somewhere within our region, we have no positive assurance that this was so. This specimen would be referred to glaucus in the key. There are 13 teeth on each side in each jaw, the teeth becoming progressively smaller from front to back. The teeth are smooth and there is no indication of cusps. The longest teeth measure 31 mm. from base to tip. In the upper jaw the third tooth is considerably smaller than the following teeth, being approximately equal in size to the eighth. The space between the third and fourth teeth in the upper jaw is wider than the spaces between other teeth. Carcharodon Muller & Henle, 1838. Carcharodon car char ias (Linnaeus). There seems to be no authentic record of the great white shark in our region, although from the distribution of the species one would expect to find it. It is recorded from southern Cali- fornia and from Chile. 8 Whitley, G. P., Rec. Austr. Mus., 20 (1), 1937: 5. 3 Philippi, R. A., Anales Univers. Chile, 71, 1887: 551. 10 Fowler, H. W., Proc. hth Pac. Sci. Congr., Java 1929, Biol. Pap. 3, 1930: 488. ■' Perez, C. C., see Philippi, R. A., Anales Univers. Chile, 71, 1887: 549. Family Cetorhinidae. Cetorhinus Blainville, 1816. Cetorhinus maximus (Gunner). Basking Shark. Range: Arctic, Antarctic and temperate seas; in the eastern tropical Pacific it is known from Ecuador and Peru and from somewhere near the Galapagos Islands. On the northern limit of the area under discussion it is known from southern California, and there is a questioned record from near Cape San Lucas. Field Characters: A very large shark with long gill-slits extending from the back and almost meeting under the throat. Caudal fin lunate, with keels on each side near the base. Back leaden gray, lower sides white. Often found drifting at the surface. (Illustration after Norman, 1937.) Size: Grows to 45 feet. Study Material: None. References: Squalus maximus, Gunner, J. E., Trondjhem sels. selskr., 3, 1765: 33, tab. 5 (orig- inal description, coast of Norway). Cetorhinus, Stevenson, C. H., Rep’t. U. S. Fish Comm. 28, 1902 (1904) : 227-228 (Peru and Ecuador, use for oil). Gudger, E. W., Science, 42, 1915: 653-656 (Occurrence in the southern hemisphere) . Basking shark, Grey, Z., “Tales of Fishing in Virgin Seas,” New York, 1925: 185 (Questionable sight record, Cape San Lucas. “I saw the dark leathery fin of a basking shark stick up out of the water. It was immense. But before we could get near enough for a picture it sank”). Cetorhinus maximus, Gudger, E. W., Science, 65, 1927: 545 (locality “not far from the Galapa- gos”). Fowler, H. W., Proc. fth Pac. Sci. Congr., Java 1929 (1930): 489 (range; includes Cali- fornia, Ecuador, Peru). Gudger, Proc. Zool. Soc. London, 1934 (1935): 877 (Contains the following statement . . and not Ceto- rhinus, which latter shark is, however, found all along the western coast of South America, and even in the vicinity of the Galapagos Archi- pelago.”) Discussion: As Norman suggests ( Discovery Reports, 16, 1937: 7) the southern basking shark, as represented by Falkland Island and southern Beebe & Tee-Van: Sharks 99 1941] South American specimens, may prove to be distinct from the northern species. The speci- mens from Peru, Ecuador and the Galapagos Islands may represent a northward projection of the range of this southern race or species of basking shark. The record of basking shark near Cape San Lucas, made by Zane Grey in “Tales of Fishing in Virgin Seas,” page 185, must be questioned until further records of this shark are secured in Gulf of California waters. The record was merely the sight of a dorsal fin which disappeared before Grey could approach near enough to secure a photograph. Family Scylliorhinidae.12 Key to genera and species of the tropical eastern Pacific.13 la. Labial folds absent or rudimentary; belly capa- ble of inflation. (Color grayish-brown, tinged with yellowish above and below; back with black cross-bars; upper parts with large round black spots Cephaloscyllium uter lb. Labial folds present; belly not inflatable. 2a. First dorsal fin originating behind the origin of the pelvics; base of the second dorsal fin shorter and wholly above that of the anal fin, the latter overlapping it before and behind; belly pale Pristiurus xaniurus 2b. First dorsal fin originating well in front of the pelvics; second dorsal fin about equal to the anal in size, and terminating slightly behind it; belly same color as rest of the body Cephalurus cephalus 12 The genera in this family are not easy to differentiate and it is possible that many of them ought to be merged or at least recognized as subgenera. We have here followed Garman, 1913, except for the use of Scylliorhinus in place of Catulus. Halaelurus chilensis (Guichenot) of Chilean and south- ern South American waters, approaches the borders of the region under consideration. It has been recorded from Mollendo, Peru, by Evermann, B. W & Radclifle, L. (Bull. U. S. Nat. A/us., 95, 1917: 3). 13 Apristurus brunneus (Gilbert). The range of this species has been noted as including the Gulf of California. However, this is not true and the species is known, as far as the literature is concerned, only from north of the United States boundary. The history of the false Gulf of California record seems to be as follows: In the original description of Catulus brunneus ( Proc . U. S. Nat. Mus., 14, 1891 (1892): 542), which is included in a paper entitled “Descriptions of thirty-four new species of fishes collected in 1888 and 1889, principally among the Santa Barbara Islands and the Gulf of Cali- fornia,” no mention is made of the type locality of the species. Jordan & Evermann. in “Fishes of North and Middle America, ” Vol 1, page 24, supplied the deficiency by stating “Gulf of California,” and this notation has been copied in a number of papers. Unfortunately, this selection of a type locality is not in accord with the known distribution of brunneus and, in addition, a checking of the type. No. 51,708, U. S. National Museum, reveals that it was taken at Albatross station No. 2396, 32° 49' N. Lat., 117° 28' 30" W. Long., in 359 fathoms, on February 4, 1889. This locality is about 10 miles west of Point La Jolla, California, quite within the generally known range of the species, and a long distance from the Gulf of California. Apristurus brunneus may thus be removed from con- sideration as a Gulf of California species, and the type locality should be changed in the literature to coincide with the notes given above. Cephaloscyllium Gill, 1861. Cephaloscyllium uter (Jordan & Gilbert). Swell Shark. Range: Monterey Bay to northern Lower California, with a single record at Acapulco, Mexico. Field Characters: Small, blunt-headed sharks with first dorsal fin far back on the body, over the pectoral fins; teeth small, tricuspid, in about four series. Grayish-brown with bands and spots of black, sometimes with white spots on the body. Belly capable of great inflation. (Illustration after Jordan & Evermann, 1900: 790 mm.). Size: Grows to about three feet. Study Material: None. References: Catulus uter, Jordan, D. S., & Gilbert, C.