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ALLAN HANCOCK FOUNDATION' PUBLICATIONS

OF THE UNIVERSITY OF SOUTHERN CALIFORNIA

First Series

ALLAN HANCOCK PACIFIC EXPEDITIONS

Volume 2 1935-1940

THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS

LOS ANGELES, CALIFORNIA

1940

ALLAN HANCOCK FOUNDATION PUBLICATIONS

ALLAN HANCOCK PACIFIC EXPEDITIONS

Volume 2 1935-1940

THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS

LOS ANGELES, CALIFORNIA

1940

CONTENTS

Pages

1. A New Brittle Star from the Galapagos Islands, by Fred Ziesen-

henne. (Plate 1) 1- 6

2. Description of A New Blennioid Fish of the Genus Acanthemble- maria from the Pacific Coast of Panama, by George S. Myers and

Earl D. Reid 7- 10

3. A New Genus of Distoraes (Trematoda) with Lymphatic Vessels,

by Harold W. Manter. (Plate 2) 11- 22

4. Parasitic Copepods Taken During the Third Hancock Expedition

to the Galapagos Islands, by Charles Branch Wilson. (Plate 3) 23- 30

5. Some Monogenetic Trematodes from the Galapagos Islands and

the Neighboring Pacific, by Frank G. Meserve. (Plates 4-10) 31- 90

6. Three New Trematodes from the Galapagos Marine Iguana Amblyrhynchus cristatus, by Paul T. Gilbert, (Plates 11-12) 91-108

7. Eight New Species of Gobioid Fishes from the American Pacific

Coast, by Isaac Ginsburg 109-122

8. Land and Brackish Water Mollusca of Cocos Island, by G. Dallas

Hanna and Leo George Hertlein 123-136

9. Nematode Parasites of the Galapagos Land Iguana, by Ashton C. Cuckler. (Plates 13-15) 137-166

10. A New Species of Nycteribiidae (Diptera Pupipara) from Islands

in the Gulf of California, by Hugh Scott. (Plate 16) 167-172

11. A Remarkable New Genus of Sea-Urchin (Spatangidae), by Hu- bert Lyman Clark. (Plate 17) 173-176

12. Marine Mollusks from Panama Collected by the Allan Hancock Expedition to the Galapagos Islands, 1931-1932, by A. M. Strong

and Leo George Hertlein. (Plates 18-23) 177-246

13. Revision of the Nemertean Fauna of the Pacific Coasts of North, Central, and Northern South America, by W. R. Coe. (Plates

24-31) 247-324/'

14. Digenetic Trematodes of Fishes from the Galapagos Islands and

the Neighboring Pacific, by Harold W. Manter. (Plates 32-50) 325-500

15. The Acanthocephala Collected by the Allan Hancock Pacific Ex- pedition, 1934, by Harley J. Van Cleave. (Plates 51-55) 501-530

16. The Geographical Distribution of Digenetic Trematodes of Ma- rine Fishes of the Tropical American Pacific, by Harold W.

Manter 531-547

Index _ 549-557

^^<Z V^^-^io

100% ]

REPORTS ON THE COLLECTIONS OBTAINED BY THE HANCOCK PACIFIC EXPEDITIONS OF VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, AND IN 1935.

A NEW BRITTLE STAR FROM THE GALAPAGOS ISLANDS

By FRED ZIESENHENNE

The University of Southern California Publications

The Hancock Pacific Expeditions

Volume 2. Number 1

Issued March, 1935

The University of Southern California Press Los Angeles, Californu

A NEW BRITTLE STAR FROM THE GALAPAGOS

ISLANDS

(With One Plate)

By FRED ZIESENHENNE The University of Southern California Invertebrate Laboratory

During the winters of 1932-33 and 1933-34 it was a privilege to be a member of a party of scientists on a zoological survey of the Galapagos Islands under the leadership of Captain G. Allan Hancock, who sponsored the Hancock Pacific Expeditions of 1932, of 1933, of 1934, and of 1935. One of the most interesting specimens taken on the 1933 Expedition was a new species of the genus Ophioplocus taken in the waters of the Galapagos Islands.

The author wishes to express his indebtedness to H. L. Clark, Museum of Comparative Zoology, for his personal and invaluable help in connection with the description of this new species and to express his appreciation to the staff of the Museum of Comparative Zoology for the opportunity of spending some weeks studying their collections.

OPHIOPLOCUS HANCOCKI, new species

Plate 1, figures 1, 2

Locality. The original specimen was taken shore collecting on the north sandy beach of Cartago Bay, Albemarle Island of the Gala- pagos Islands at low tide, Feb. 13, 1933. It was collected from beneath surface rocks in a sandy-covered tide pool in a foot of water and partially imbedded in the sand. Its coloration blended in with the sand so that it could easily be overlooked.

An additional specimen was taken on a rocky tide flat, again em- bedded in sand under surface rocks on Jan. 20, 1934, Station 168-34. Another was collected at low tide in Academy Bay, Indefatigable Isle of the Galapagos Islands.

[ 1 ]

2 THE HANCOCK PACIFIC EXPEDITIONS VOL. 2

Three specimens were taken shore collecting in a tide pool a quarter mile south of Ritter's Landing at Black Beach, Charles Isle of the Galapagos Islands, Station 199-34.

Description. Disk 13 mm. in diameter, arms 35-37 mm. long. Disk covered with a coat of rather coarse scales, smaller ones min- gled with the larger, the latter slightly swollen making the whole surface rough and irregular; primary plates small but distinct; radial shields very small, nearly or quite concealed by numerous small disk scales; interradial margins of disk sharply defined by 5-7 large plates, of which the median is largest. Arm segments wider than long; dorsal plates broken up into a large number (20-30) of small polygonal plates of diverse sizes, forming a remarkably smooth pavement continuous with the disk covering; the distal lateral plate on each side is larger than the rest. Interbrachial areas below cov- ered with fine scales; genital slits about equal to the three basal arm segments. Oral shields pentagonal with lateral and distal cor- ners rounded; madreporite nearly circular; adoral plates medium, swollen, longer than the distal width, separated distally by the first ventral armplate but meeting within; oral papillae five or six on each side, penultimate twice as large as others. First under arm plate small, triangular, or low pentagonal, succeeding plates squarish, as wide as long. Side arm plate more or less covered, especially orally, by a shagreen-like skin; each one bears three stout flattened, bluntly pointed spines, as long as segment; lowest spine slightly the longest. Tentacles scales three or four, two larger ones on proximal side of pore and two or one much smaller on distal side; distally the scales become less distinct and often only one is evident.

Color in alcohol, disk cream yellow with irregular brown mark- ings, in some of which the radial shields are usually included; arms cream color with brown bands on every sixth segment; arm spines nearly white; interbrachial areas below cream color speckled with about a dozen dull purple spots; proximal ventral plates more or less dusky; distally the brown bands of the arm are indicated by dusky ventral plates. In the dried specimen the yellow tint is lost and the disk and upper surface of the arms are a light grey with the dark markings conspicuous.

Types.— i:\iQ type is deposited at the United States Museum. The co-types are deposited at: the Museum of Comparative Zoology, Cambridge, Mass., number 4834; the Zoological Museum, University

NO. 1 ziesenhenne: a new brittle star 3

of Copenhagen, Denmark; The University of Southern California, Los Angeles, Calif., and the Velero III Collection, Los Angeles, Calif.

Remarks. This species is remarkably interesting because the genus has a curious discontinuous distribution. There is one species in Japanese waters, one in the East Indies and Tropical Australian regions, one on the Southern Australian Coast, one in New Zealand, one along the Central American coast and north to Southern Cali- fornia, and now this new and particularly well-marked species from the Galapagos and presumably endemic there. It is instantly recog- nizable by the numerous plates on the upper side of the arm seg- ments, their small size, and the closely fitted smooth pavement which they form. More material may show that the coloration is also distinctive.

^ V>**.

THE HANCOCK PACIFIC EXPEDITIONS VOL. 2

EXPLANATION OF PLATE

Fig. 1. Ophioplocus hancocki, new species, dorsal view x .7 Fig. 2. Ophioplocus hancocki, new species, ventral view x 2.3

(Photograph of para-type at The University of Southern California)

NO. 1

ziesenhenne: a new brittle star

PL. 1

rkDuir\Di r\mic uAMrr^r^i^i

REPORTS ON THE COLLECTIONS OBTAINED BY THE HANCOCK PACIFIC EXPEDITIONS OF VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, AND IN 1935.

DESCRIPTION OF A NEW BLENNIOID FISH

OF THE GENUS ACANTHEMBLEMARIA FROM

THE PACIFIC COAST OF PANAMA

By GEORGE S. MYERS and EARL D. REID

The University of Southern California Publications

The Hancock Pacific Expeditions

Volume 2, Number 2

Issued December, 1936

The University of Southern California Press Los Angeles, California

Copyright 1936

by

The University of Southern California

DESCRIPTION OF A NEW BLENNIOID FISH OF

THE GENUS ACANTHEMBLEMARIA FROM

THE PACIFIC COAST OF PANAMA*

By GEORGE S. MYERS, Stanford University, and EARL D. REID United States National Museum

Among the fishes obtained by Dr. Waldo L. Schmitt, Curator of Marine Invertebrates in the United States National Museum, during the 1935 cruise of Capt, .G. Allan Hancock's yacht Velero III, we find a most interesting new species of the genus Acantheryiblemaria. The three hitherto-known species of the genus are all West Indian (Metzelaar, 1919, p. 159; Beebe and Tee-Van, 1928, pp. 244-249).

Acanthemblemaria hancocki, new species

Holotype. U.S.N.M. 102015, a specimen 31.8 mm. in standard length, taken February 4, 1935, on the outer side of the smaller, westernmost island of the Secas Islands, Pacific coast of Western Panama. Hancock Pacific Expedition, 1935.

Paratypes. U.S.N.M. 102016, two specimens 30.8 and 31 mm. in standard length; same data as holotype.

Dorsal XXII to XXIII, 13 to 14. Anal II, 24 to 25. Pectoral 13. Pelvic 3. Caudal 16. Body moderately elongate, trunk compressed, greatest depth at origin of pectoral. Occipital region of skull rather bulging on each side, but upper profile of head continuously decurved from dorsal fin to snout tip. Head 3.7 to 3.9 in standard length, depth 5.8 to 6.1, predorsal distance 5 to 5.2, preanal distance 2.3 to 2.5. Pectoral 1.2 in head length (measured to upper angle of gill opening), pelvics 2.3, caudal 1.5, snout 7.7 to 7.9, interorbital 6.4 to 6.7, maxillary 1.8 to 2.3, extending slightly past posterior rim of orbit.

* Published with the permission of the Secretary of the Smithsonian Institution.

[ 7]

8 THE HANCOCK PACIFIC EXPEDITIONS

VOL.

Teeth in upper jaw in a strong outer row which extends back- ward to opposite middle of palatine patch, and a series of extremely minute inner teeth. Vomer with four strong teeth arranged in a square. Palatine patches with two rows of teeth, the patches being elongate-oval in shape. Teeth of lower jaw in a single strong outer row with a fe^'^ very small teeth set in two irregular rows behind the main one at front of jaw. Both upper and lower jaws are rather expanded and flattened in front (the symphyses indented) and then rather suddenly constricted as the rami turn and run backwards. This formation of the jaws is apparently that described by Beebe and Tee-Van (in other species) as that of an old-fashioned key-hole. It might better be described as like the jaws of Hippopotamus. The main jaw teeth are strong though rather short, pointed, and slightly compressed in front. The front teeth in each jaw flare outward slightly.

Entire front of upper part of head, forward of the vertical of the posterior rim of orbit, covered with fine blunt spines. The spinous area includes the whole frontal and preocular region, the suborbitals, and a patch on top of the head behind the eyes extending backward in a blunt point toward (but not reaching) the vertex of the supra- occipital region. The interorbital is strongly concave, forming a trough in the middle, and is armed with three rows of spines on each side, the outer row being part of the single circumorbital spiny ring. This ring is complete except directly behind the eye. Orbital tentacle short, apparently simple. Nasal tentacle longer and multifid, but not as long as that of A. arborescens. Opercle and preopercle naked. A group of five or six pores on either side of nape about opposite origin of dorsal fin. Opercle ends above in a free, hook-like membrane supported by the branchiostegal rays, which reach notably above the point of attachment of the gill-cover.

Vertical fins of moderate height, soft rays longer than spines, the last rays attached at caudal base by a membrane. Origin of dorsal above preopercle, directly at base of cranium, which has no supra- occipital crest. Pelvics inserted in front of pectoral base.

Body light straw-colored, the head blackish with darker spots and lighter marblings, the principal dark area being a large hourglass- shaped saddle set transversely across the occiput and extending down on opercles to opposite lower rim of eye. About four brown dots on margin of opercle. Body with two main longitudinal rows

NO. 2 MYERS AND REID: A NEW BLENNIOID 9

of dark brown spots, as large as eye in front but diminishing rapidly posteriorly, the upper row along the base of the dorsal and encroach- ing a little on the basal fin membranes, the lower row at mid-line of body. Another less conspicuous row of spots along anal base, these chiefly on the membranes. A single row of very fine dots just below the dorsal series and set alternately with each dorsal blotch. A similar row between the main central series of blotches and the anal series; this row may be very indistinct or nearly absent. Dorsal and anal faintly and narrowly bordered with dark. Pectorals and caudal clear. Pelvics brownish. Often the first few dorsal spines and their membranes dark brownish, fading posteriorly. The entire color effect is that of a black-headed, straw-colored fish with longitudinal series of spots which decrease in size posteriorly.

We are not certain to which of the three described species of Acanthemblemaria our new species is most closely related. Beebe and Tee-Van separate spinas a of Metzelaar from the others by the supposed lack of small teeth behind the main jaw series. It seems probable to us that Metzelaar's fish also had these small teeth, as they are very difficult to detect without the use of tooth-impressions made with modeling clay. Beebe and Tee-Van further separate arborescens from variegata on the profile of the head and the area of its spinosity, on the structure of the orbital tentacle, and on the color. The head profile of our form differs from that of the other three, and the area of spinosity on the top of the head is hard to compare without actual specimens of the other species in hand. Our species diifers from arborescens and spinosa and agrees with variegata in the simple ocular tentacle, but agrees with arborescens and differs from the other two in the shape of the jaws and mouth as illustrated in the figures. It differs widely from all three in the unusual coloration.

Lukli^A

10 THE HANCOCK PACIFIC EXPEDITIONS VOL. 2

LITERATURE CITED

Beebe, William, and John Tee-Van

1928. The fishes of Port-au-Prince Bay. Haiti, with a summary of the known species of marine fish of the island of Haiti and Santo Domingo. Zoologica. Sci. Contrib. N.Y. Zool. Soc, vol. 10, no. 1, pp. 1-279.

Metzelaar, Jan

1919. Report on the fishes collected by Dr. J. Boeke in the Dutch West Indies, 1904-1905, with comparative notes on marine fishes of tropical West Africa. In: Boeke. J., Rapp. voorl. onderz. toest. Visscherij Industr. Zeeprod. Kol. Curacao, tweede ged., 1919, bijl. 1, pp. 1-315. Tlie Hague.

REPORTS ON THE COLLECTIONS OBTAINED BY THE HANCOCK PACIFIC EXPEDITIONS OF VELERO in OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935, IN 1936, AND IN 1937.

A NEW GENUS OF DISTOMES (TREMATODA) WITH LYMPHATIC VESSELS

By H. W. MANTER

The University of Southern California Publications

The Hancock Pacific Expeditions

Issued June, 1937

The University of Southern California Press Los Angeles, California

A NEW GENUS OF DISTOMES (TREMATODA) WITH LYMPHATIC VESSELS*

v>* .

(With One Plate)

suj| i-i ^ t^ A

H. W. Manter \ti\ -^^-^

University of Nebraska

The trematodes described in this paper are but two of over 100 species collected from marine fishes in 1934, during the third G. Allan Hancock Expedition to the Galapagos Islands. The author's presence on this expedition was sponsored in part by the Carnegie Institution of Washington. A brief preliminary report on the trema- todes collected has been made (Manter, 1934) and a more complete report on the digenetic forms is in preparation. An early description of these two forms is felt justified in view of their significance in connection with the phylogeny of the Distomata. The author has already indicated (Manter, 1935) a relationship between certain allocreadiid-like distomes (Megasolena Linton and Hapladena Lin- ton) and amphistomes. The new genus described below further sub- stantiates such a view and indicates that the Anallocreadiinae in particular may be involved. A discussion of these relationships will follow a description of the new species.

Apocreadsum mexicanum, new genus, new species (Plate 2, figs. 1-3)

Host: Labrisomiis xanti Gill

Position: Intestine

Locality: Tangola Tangola, Mexico

Incidence: 18 specimens from a single host

The body is elongate, tapering slightly and bluntly rounded at the anterior end, pointed at the posterior end, much flattened, espe- cially posterior to midbody where the edges of the body become very thin and thrown into frill-like folds. The cuticula is scaled as far back as midbody. Mature specimens measure from 2.151 to 4.110 mm. in length by 0.757 to 1.096 mm. in greatest width. The body

* Studies from the Zoological Laboratories, the University of Nebraska, No. 191.

[ 11 ]

12 THE HANCOCK PACIFIC EXPEDITIONS VOL. 2

is approximately equally wide, except at the anterior and posterior fourth. The acetabulum is well anterior to midbody, the forebody being usually 1/4 to 1/5 total body length. Both suckers are sub- circular with a tendency to be slightly longer than wide. The oral sucker is 0.225 to 0.315 mm. in diameter. The acetabulum is 0.352 to 0.502 mm. in diameter. Its aperture is transverse. The sucker ratio is approximately 2:3 or 3:5. Young specimens show a few pigment granules dorsally in the forebody but these are lacking in older specimens.

There is a short but distinct prepharynx. The pharynx is longer than wide, 0.142 to 0.202 by 0.112 to 0.165 mm. Its anterior fourth is modified as a sphincter region composed of circular muscles (sug- gesting the character of the pharynx in Gyliauchen) while the pos- terior region is composed of radial muscles. There is a distinct esophagus somewhat shorter than the pharynx. The intestinal bifur- cation is approximately midway between the suckers. The ceca are narrow and extend to a point a short distance from the posterior end where the body begins its rather abrupt tapering to the posterior tip. Each cecum ends blindly.

The excretory vesicle is a long narrow tube extending anteriorly from the pore at the posterior tip of the body to the posterior testis where it spreads slightly to right and left and narrows to become a collecting tube on each side. Each collecting tube shortly after it leaves the vesicle forks into two tubules both extending forward, both at first median to the cecum, the larger tubule median to the smaller. Anterior to the acetabulum they are both lateral to the cecum. They seem to end near the level of the pharynx. Posterior to the level of the testes a very small excretory tubule can be seen on each side. These two posteriorly directed tubules arise at the same point where the anterior tubules unite. They extend to the posterior end of the body.

The lymphatic system consists of four longitudinal vessels close to the intestinal ceca, sometimes median, sometimes dorsal and ventral. Two of these lymphatic vessels extend anterior to the oral sucker to the extreme anterior end of the body where they end blindly. The longitudinal vessels do not give off" side branches ex- cept in the posterior half of the body. Shortly behind the testes vesicle-like portions of the lymphatic system appear in the extreme lateral regions of the body. These are especially numerous near the

NO. 3 manter: a new genus of distomes 13

posterior end of the body where they are obvious in toto-mounts. Posterior to the testes each of the four vessels spUts to form two making a total of four pairs. Each vessel is much branched, the ends of the branches extending to near the edge of the body. These tips are often swollen (plate 2, fig. 2).

The genital pore is median close to the anterior edge of the acetabulum. The testes are more or less rectangular in outline, slightly lobed, tandem, close together, approximately in the middle of the body. Except in young individuals (where the testes are of about equal size) there is a distinct tendency for the anterior testis to be wider than long, smaller and less lobed while the posterior testis tends to be longer than wide, larger and more deeply lobed. The posttesticular space is very long, sometimes more than Yz body length. A large, elongated sac-like seminal vesicle occurs immediate- ly posterior to the acetabulum and overlapping the ovary. Anter- iorly it narrows into a fine tube which continues without modifica- tion to near the anterior edge of the acetabulum where it joins the uterus to form a simple tubular genital sinus. Prostate gland cells are lacking unless represented by a few scattered cells around the male duct. A cirrus and cirrus sac are lacking. The narrow straight tube from seminal vesicle to genital pore is not muscular and since the pars prostatica cannot be distinguished from a cirrus portion, the tube might be termed the ejaculatory duct. It seems to have the same structure after its union with the uterus to form the ductus hermaphroditlcus or genital sinus.

The ovary is spherical, midway between the anterior testis and the acetabulum, slightly to the right, just median to the right cecum. Mehlis' gland is well-developed, lying between ovary and anterior testis. A large flask-shaped seminal receptacle extends anterior to the ovary almost to the acetabulum. Laurer's canal is well-develop- ed, coiled, and opens dorsally at mid-ovary level. The uterus is pre- testicular filling most of the area between testes and acetabulum, wholly to the left of the ovary and largely to the left of midbody axis. It becomes a straight tube dorsal to the acetabulum and joins the male duct near the anterior edge of the acetabulum. The eggs are fairly thin-shelled, 61 to 67 by 31 to 34 ;u. The vitelline follicles extend from the level of the ovary to near the posterior end of the body. In 13 specimens studied the follicles reached the posterior border of the acetabulum In 2 (In which the ovary also was far for-

14 THE HANCOCK PACIFIC EXPEDITIONS VOL. 2

ward) and in none did they reach the extreme posterior tip of the body. The vitellaria largely fill the body posterior to the testes and form two longitudinal intercecal, posttesticular areas.

GENERIC DIAGNOSIS OF APOCREADIUM

Elongate distomes with body much flattened posterior to mid- body where the edges are very thin. Acetabulum anterior to mid- body, larger than oral sucker. Pharynx well developed with an an- terior region of circular muscles. Ceca extending not very far apart to near posterior end. Testes in midbody region, tandem, intercecal, close together. Seminal vesicle large, undivided, sac-like. Cirrus and cirrus sac lacking. Prostate cells poorly developed. A tubular genital sinus present. Genital pore median at anterior edge of acetabulum. Ovary spherical, pretesticular, slightly to the right. Mehlis' gland large, postovarian; Laurer's canal and seminal receptacle present. Uterus pretesticular, largely to the left. Vitellaria follicular in sides of body, confluent posterior to testes. Excretory vesicle I-shaped with 2 pairs of anterior and 1 pair of posterior tubules. Lymphatic sys- tem of 4 large longitudinal vessels branching at least in posterior half of body. Type species: Apocreadium mexicanum.

SPECIFIC DIAGNOSIS OF Apocreadium mexicanum

(Measurements in mms.)

Body rounded anteriorly, pointed posteriorly; scaled to mid- body; 2.151 to 4.110 by 0.757 to 1.096. Acetabulum 1/4 to 1/5 from anterior end, 0.352 to 0.502 in diameter, with transverse aperture; oral sucker 0.225 to 0.315 in diameter. Prepharynx and esophagus present; intestinal bifurcation midway between suckers. Four longi- tudinal vessels branched in posterior half of body. Genital pore me- dian at anterior edge of acetabulum. Seminal vesicle just posterior to acetabulum, overlapping ovary; genital sinus tubular, shorter than ejaculatory duct. Ovary spherical; seminal receptacle extend- ing anterior to ovary; uterus to left of ovary; eggs 61 to 67 by 31 to 34 /x; vitellaria from near posterior edge of acetabulum to near posterior edge of body.

Host: Labrisomus xanti Gill

The name Apocreadium is from apo: 'away from and creadium and implies the fundamental differences between this trematode and the AUocreadiidae. The name mexicanum is for the locality.

NO. 3 manter: a new genus of distomes 15

Apocreadium longisinosum, new Species

(Plate 2, figs. 4-7)

Hosts: Cheilichthys anmilatus (Jenyns)

Albermarle Island and Charles Island, Gala- pagos Islands

Spheroides angusticeps (Jenyns) Charles Island, Galapagos

Position: rectum

Incidence: 2 to 10 in a host, total of 15 collected from 3 hosts.

The body is orange-yellow in its posterior half, unspined, more or less flattened, 6.57 to 9.65 by 1.552 to 2.403 mm., widest about at midbody, tapering toward each end. A 4.650 mm. specimen was immature. The posterior third of the body is thin and flexible with numerous lateral folds. It tapers sharply to a pointed posterior end. The anterior half of the body is more plump, smooth, and tapers gradually. A small, fleshy preoral lobe is present. The oral sucker is subcircular but usually slightly longer than wide, 0.375 to 0.532 mm. in transverse diameter. The acetabulum is about % body length from the anterior end, is longer than wide, 0.675 to 0.885 mm. in transverse diameter. Its aperture is longitudinal. The sucker ratio is approximately 5:8. The forebody measures 1.360 to 2.430 mm.

There is a fairly short prepharynx (about >^ pharynx length). The pharynx is usually somewhat pyriform in shape. The anterior third is more narrow, provided with a larger number of circular muscles, and separated from the posterior region by a very slight constriction. Muscles extend from the oral sucker to the pharynx outside the prepharynx. The esophagus is approximately the same length as the prepharynx. The intestinal bifurcation is usually a little nearer the oral sucker than the acetabulum but it may be ap- proximately midway between the suckers. The narrow ceca extend some distance in from the body margins to within a short distance of the posterior end. They do not reach the posterior end and may fail to do so by some distance. One curious abnormality involved the left cecum which was almost completely degenerate except for a short normal-appearing stub barely reaching beyond the bifurca- tion and ending abruptly. The remainder of the cecum was repre- sented by a few strands of fine fibrous tissue.

16 THE HANCOCK PACIFIC EXPEDITIONS VOL.2

The genital pore is median very closely anterior to the acetab- ulum. It may even be directly ventral to the anterior edge of the acetabulum. The testes are immediately posterior to midbody, tan- dem, close together, lobed, squarish in shape. The posterior testis is usually slightly longer. The posttesticular space varies from 2.497 to 4.455 mm. being always considerably longer than the forebody. The seminal vesicle is a large, elongate, thin-walled sac, free in the parenchyma, extending backward from near the posterior edge of the acetabulum almost to the ovary from which it is separated by the seminal receptacle. The pars prostatica is about the same length as the seminal vesicle. It extends uncoiled diagonally forward dorsal to the acetabulum or, rarely, along the right side of the acetabulum. Its lumen is narrow and smooth, its wall fairly thick and cellular, surrounded by a few prostatic gland cells. These flattened and gran- ular gland cells lie free in the parenchyma and are most numerous near the vesicle. The uterus enters the pars prostatica dorsal to the acetabulum to form a long tubular slightly muscular ductus herm- aphroditicus or genital sinus. This tube bends ventrally toward the genital pore at the anterior edge of the acetabulum or may seem to bend back to reach the genital pore from an anterior direction (plate 2, fig. 5) but this appearance may be due to flattening of the speci- men. The genital sinus is approximately the same length as the pars prostatica. Its lumen is wide, its wall fairly thin but muscular and surrounded by a few rounded non-granular cells.

The ovary is globular, pretesticular, to the right near the right cecum. It is separated from the anterior testis by a short space occupied by Mehlis' gland and the yolk reservoir. The uterus arises from the posterior side of the ovary and extends back as far as the anterior testis whence it coils forward to occupy the intercecal space to the left and anterior to the ovary. It joins the pars prostatica dorsal to the acetabulum as noted. A large seminal receptacle is present anterior to the ovary adjacent to the seminal vesicle. It connects to the oviduct posterior to the ovary, Laurer's canal is well developed, coiled, opening on the dorsal surface just anterior to the ovary. Eggs measure 88 to 102 by 48 to 60 ix, usually about 95 by 54 fi. The vitelline follicles extend from the level of the ovary to the posterior end of the body. At first extracecal, they become con- fluent posterior to the testes.

^0. 3 manter: a new genus of distomes 17

The excretory system is like that of Apocreadium wexicanum. The narrow excretory vesicle gives rise near the posterior testis to 2 pairs of anteriorly directed tubules, one pair larger than the other. Both pairs extend foru^ard at least as far as the acetabulum but only one pair seems to reach as far as the oral sucker. From the common stem of each pair near the median vesicle a single sinuous tubule passes posteriorly on each side.

The lymph vessels are well developed. They are considerably branched in the posterior half of the body as In A. mexicanum. The branches run almost parallel with the stems, diverging gradually toward the body surface. They are not swollen at their tips as are such branches in A. rnexicamnn. The lymph vessels of the forebody also branch but here the branches are shorter and may extend in any direction. Because of the courses taken by the branches, the number of main stems of the lymph system is very difficult to deter- mine. For some distance posterior to the testes there seem to be 4 pairs of longitudinal tubes, although 2 pairs extend farther back than the others. In the region of the acetabulum there seem to be 2 pairs. An accurate count was not possible in the forebody. In most specimens one pair extended into the preoral lobe. Evidently the lymph system Is very similar to that of A. mexicanum.

Lymphocytes or at least large cells of some kind (plate 2, fig. 7) are not infrequent within the lymph vessels. These cells seem to have been amoeboid. They measure 14 to 19 /u, in diameter which Is as great as the diameter of most of the lymph vessels. The cyto- plasm of these cells Is finely granular, the nucleus staining very deeply, much more deeply than those of other cells.

SPECIFIC DIAGNOSIS OF Apocreadium longisinosum

(Measurements in mms.)

Body tapering toward each end, pointed at posterior end, widest at midbody, 6.57 to 9.65 by 1.552 to 2.403, In Hfe orange-yellow In color. Oral sucker 0.375 to 0.532 In diameter; acetabulum }i from anterior end, 0.675 to 0.885 In diameter, with longitudinal aperture. Genital pore median close in front of acetabulum. Short prepharynx, pharynx 0.210 to 0.292 (length) by 0.225 to 0.315 (width), anterior third slightly modified; esophagus short; bifurcation about midway between suckers; ceca narrow extending to near posterior end. Testes tandem, close together, slightly lobed, squarish, just poster-

18 THE HANCOCK PACIFIC EXPEDITIONS VOL.2

icr to midbody. Seminal vesicle elongated sac-like from acetabulum to near ovary; pars prostatica about as long as vesicle, straight; ductus hermaphroditicus a simple muscular tube as long as pars prostatica. Ovary globular; Mehlis' gland posterior to ovary; semi- nal receptacle anterior to ovary; uterus between testes and acetab- ulum; eggs 88 to 102 by 48 to SO/x; vitellaria from ovary to pos- terior end, confluent behind testes. Excretory vesicle extending to testes; 2 pairs of anterior and 1 pair posterior collecting tubules. Lymph vessels well developed, much branched, apparently funda- mentally 2 pairs of longitudinal stems forking to form 4 pairs along much of body length. Type host: Cheilichthys annulatus. Other host: Spheroides angusticeps, a related fish. Type locality: Galapagos Islands.

The name longisinosum refers to the long genital sinus.

Comparisons. A. longisinosu77i is more than twice larger than J. mexicanum and the body is relatively wider. The aperture of the acetabulum is longitudinal rather than transverse. The vitellaria do not nearly reach the acetabulum as they do in J. mexicanum, a dif- ference correlated with the larger uterus in A. longisinosum. In A. longisinosum the genital sinus is much longer; the eggs much larger (maximum length 102 ^i compared with 67 p.) ; the lymph vessels more branched anteriorly. In spite of these differences the species are very similar and clearly congeneric.

There are genera of the Allocreadiidae with the cirrus sac weak- ly developed or lacking, for example the Anallocreadiinae and Opecoeliinae, but Apocreadium diff'ers from most in its tubular geni- tal sinus and from all in its lymphatic system. It is probably signifi- cant that the Anallocreadiinae which lack a cirrus sac also possess a tubular genital sinus described as "a common tube" in the form of an "unspecialized cloacal invagination" by Simer (1929, p. 564) for Anallocreadium armatum; as a "long genital sinus" by Manter (1926, p. 87) for Homalometron pallidum; as "an invaginated clo- aca" by Hunter & Bangham (1932, p. 138) for Anallocreadium pear- sei; but as a "genital atrium" by Manter (1936, p. 34) for Crassi- cutis cichlasomae. In this latter case however, the "atrium" may be tubular in form.

The genus Apocreadium then shows evidence of relationship to the Anallocreadiinae. On the other hand, however, its lymphatic vessels, the structure of the pharynx and the excretory system sug-

NO. 3 manter: a new genus of distomes 19

gest the genera Megasolena and Hapladena for which Manter (1935, p. 438) named the subfamily Megasoleninae. The essential difference is the presence of an hermaphroditic sac in the Megasoleninae. Apo- creadium seems to stand almost midway between these two subfami- lies. If Included in the Megasoleninae, the subfamily (and family) description must be altered to include forms with neither hermaphro- ditic nor cirrus sac; if included in the Anallocreadilnae the subfamily must be extended to include forms with a lymphatic system. For the present, the writer prefers to recognize the lymphatic vessels as of fundamental significance, especially since their presence is again as- sociated with pharyngeal modifications and to classify Apocreadium in the Megasoleninae.

Discussion. For many years It has been the custom to classify digenetic trematodes Into three groups, the Amphlstomata, Mono- stomata, and DIstomata. But it has been increasingly apparent that these divisions are heterogeneous and not natural. Some monostomes (e. g. the Angiodictyidae) are actually amphistomes which have lost their posterior sucker. Other monostomes are evidently distomes which have lost the ventral sucker. In other words, members of these groups may show closer relationship to one of the other groups than to members of its own group. Amphistomes are generally considered as the most primitive. Little study has been made of possible rela- tionship between amphistomes and distomes. Dawes (1936, p. 177) remarks: "Nous savons vralment peu de chose sur les relations qui existent entre les DIstomata et les Paramphlstomlda; c'est un point qui est vislblement neglige par les zoologlstes." The author, however (Manter, 1935), has found strong evidence of such relationship exactly where It would be most expected, namely among trema- todes of fish. It even seemed necessary to classify two distome genera (Megasolena and Hapladena) among the Paramphlstomlda. These two genera showed certain features suggesting the family Allocreadl- Idae where Megasolena at least was once classified.

Apocreadium is still more evidently allocreadiid-like. It serves to link the Paramphlstomlda not only to the Allocreadildae but to the Anallocreadilnae. But Apocreadium can be included In the Mega- soleninae especially if the lymphatic system Is to be emphasized. There Is, In fact, a fairly well graded series of forms between the amphistomes such as Gyllauchen and Opistholebes through Para- gyliauchen, Apocreadium and the Anallocreadilnae to the Lepo-

20 THE HANCOCK PACIFIC EXPEDITIONS VOL. 2

creadiinae. Even the position of the acetabulum is intermediate in some forms such as Paragyliauchen chaetodontis Yamaguti. Mega- solena and Hapladena are definitely associated with such a series but differ from the others in their pecuHar hermaphroditic sac. There results a plausible conclusion that the large distome family Allocreadiidae probably evolved from amphistome ancestors. Or the amphistomes may have evolved from allocreadiid ancestry.

Type specimens of the new species described in this paper are deposited in the United States National Museum. Paratypes are de- posited at The University of Southern California and in the author's collection.

NO. 3 manter: a new genus of distomes 21

literature cited

Dawes, Ben

1936. Sur une tendance probable dans revolution des trematodes dig^n^tiques. Ann. Parasit., 14:177-182.

Hunter, George W. & Ralph V. Bangham

1932. Studies on fish parasites of Lake Erie I. New trematodes (Allocreadi- idae). Trans. Amer. Micros. Soc, 51:137-152.

Manter, H. W.

1926. Some North American fish trematodes. III. Biol. Mon., 10:1-138.

1934. Preliminary observations on trematodes from the Galapagos Islands and neighboring Pacific. Ann. Rept., Tortugas Lab., Carnegie Inst. Wash., Year Book No. 33:260-261.

1935. The structure and taxonomic position of Megasolena Linton 1910 (Trematoda) with notes on related trematodes. Parasit., 27:431-439.

1936. Some trematodes of cenote fish from Yucatan. Carnegie Inst. Wash., Pub. No. 457, 33-38.

Simer, Parke H.

1929. Fish trematodes from the Lower Tallahatchie River. Amer. Mid. Nat., 11:563-588.

22 THE HANCOCK PACIFIC EXPEDITIONS VOL.2

EXPLANATION OF PLATE 2

All figures were drawn with the aid of a camera lucida. The projected scale has the value (in mms.) indicated for each figure. Abbreviations: ac, acetabulum; ce, intestinal cecum; ex, excretory vesicle; gp, genital pore; gs, genital sinus; /, lym- phatic vessel; pp, pars prostatica; sr, seminal receptacle; sv, seminal vesicle; ut, uterus.

Fig. L Apocreadium mexicaimm. Dorsal view.

Fig. 2. A. mexkanum. Frontal section through posterior half of the body, showing the branching lymphatic vessels.

Fig. 3. A. mexicanum. Cross-section through the region of the seminal re- ceptacle.

Fig. 4. A. longisinosum. Ventral view.

Fig. 5. A. longisinosum. Terminal reproductive organs.

Fig. 6. A. longisinosum. Cross-section through anterior portion of the pharynx.

Fig. 7. A. longisinosum. Portion of two lymphatic vessels showing lympho- cytes.

NO. 3

manter: a new genus of distomes

PL. 2

REPORTS ON THE COLLECTIONS OBTAINED BY THE HANCOCK PACIFIC EXPEDITIONS OF VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935, IN 1936, AND IN 1937.

PARASITIC COPEPODS

TAKEN DURING THE THIRD HANCOCK

EXPEDITION TO THE GALAPAGOS ISLANDS

By CHARLES BRANCH WILSON

The University of Southern Calieornia Publications

The Hancock Pacific Expeditions

Volume 2, Number 4

Issued June, 1937

The University of Southern California Press Los Angeles, California

PARASITIC COPEPODS TAKEN DURING THE THIRD HANCOCK EXPEDITION TO THE GALAPAGOS ISLANDS

(With One Plate)

*

Charles Branch Wilson ' *

The New England Museum of Natural History, Boston, Massachusetts A

•<# 7'

The valuable collections made during the third Hancock Expedi- tion to the Galapagos Islands included the copepods parasitic upon fish. These were gathered not only from the local fish around the islands but also from those captured during the passage to the islands and back. There are thus included among the hosts, fish from the Pacific coasts of Mexico, Central America, Colombia, and Ecuador as well as those from the immediate vicinity of the Gala- pagos Islands.

The parasites were collected and preserved by Dr. H. W. Man- ter of the University of Nebraska, who accompanied the expedi- tion, and were sent to the author for identification. The host identi- fication is incomplete in one or two instances since the personnel of the expedition did not include an ichthyologist.

Upon examination the collection of parasitic copepods thus ob- tained has proved to possess peculiar value and interest. This is due chiefly to the exceptional confirmation they aff'ord of species al- ready established but far removed in time, host, or habitat. Practi- cally every one of the species here enumerated contributes new and important information to supplement previous records. This appears in the re-establishment of one species which had been virtually for- gotten, since it had never been reported after its first discovery 75 years ago. Two other species almost as old have hitherto included but a single sex, in the one case the male, in the other the female. In both instances the missing sex is here supplied and is described and fig- ured for the first time. Furthermore, these records furnish an abun- dance of new