FISH PARASITES COLLECTED AT WOODS HOLE. 
271 
namely, one cliicken wing with the feathers on it, two slices of beefsteak, a few pieces of cucumber 
rind, two large pieces of “sea pork,” a piece of rope yarn, partly raveled out, with other ddbris. 
Evidently a bucket of waste from the cook’s galley of some passing vessel had been thrown over- 
board, and the shark had scooped up the whole mess. 
Large numbers of Thysanocephalum crisp urn (Cestode Parasites of Fishes, p. 148), large and stnall^ 
with enormous numbers of free proglottides in the spiral valve. The scolices were found attached to 
the mucous membrane. The pseudobothria, in such cases, were expanded into a flat limbriated disk 
and closely adherent to the mucous membrane. These cestodes were counted and a number of them 
measured. There were 56 with mature proglottides and 238 young. The latter ranged in length from 
30 to 300 mm. The average of 1 1 representative forms was 128 mm. Strobiles, which had ripe pro- 
glottides, measured 1.25 meters. This represents an actual total length of something like 100 meters; 
or, allowing for the maturity of the small specimens, a potential length of 367 meters (approximately 
i mile), without taking into account the free proglottides, of which there were immense numbers. 
Acanthocheilus nidifex sp. nov. (see Part II, page 303, for description) in crypts in stomach-wall 
and free in pylorus. 
(2) August 19; one (2.5 meters in length); stomach contained numerous jaws of squids, some 
of them of good size; various bones, skull of a fish, numerous ear-hones of fish, the operculum of a 
mollusk ( Lunatia ), seaweed ( Fucus ), sand and gravel, and a nondescript piece of animal tissue about 
the size of one’s hand, probably the remains of the pectoral fin of a goose-fish. 
Large numbers of Thysanoceplialum crispum, as in every specimen of this shark I have examined, 
in spiral valve. Also a few small forms not yet identified, heads resembling those of the genus Spon- 
giobothrium. There is, however, a fleshy anterior median eminence on the head. The worms are 
small, and before killing exhibited a tendency to become convoluted. 
There were also several free proglottides of an altogether different kind from those of Thysano- 
cephalum, of which, as usual, there were enormous numbers. The eggs of Thysanoceplialum are fusiform 
in shape, an unusual form among cestode eggs. 
Tetrarhynchus bicolor (Larval Cestode Parasites of Fishes, pp. 813-815, pi. lxviii, figs. 1-6), 36 
specimens, firmly attached to stomach-wall, where they had formed deep pits, extending into the mus- 
cular layers. Head and neck white, back of collar yellowish. These specimens, when removed from 
their host and placed in sea- water, contract and expand actively and assume a great variety of shapes. 
Two imperfect strobiles without scolices were found in the stomach. Upon sectioning they were 
found to he identical with sections of Thysanoceplialum and were so identified. I do not know how to 
account for their presence in the stomach. 
Acanthocheilus nidifex as in shark examined on August 11. 
Pathological conditions of pylorus of Galeocerdo tigrinus. — The pylorus of each of the specimens ol 
leopard shark examined was occluded by what appears to be a colloid tumor developed in the sub- 
mucosa, pi. 42, fig. 102. Although occurring in different places in the two cases they were of the 
same essential structure in each. A brief description of the first is given. The tumor was first 
encountered at its anterior end while slitting the pylorus with scissors from the anterior end. It 
presented a smooth globular stopper-like surface, which apparently completely occluded the lumen of 
the pylorus. 3S T o passage could be found on passing a probe around the periphery of the tumor. On 
cutting into the lumen at the posterior end of the tumor a narrow passage was discovered, which led 
back beside the tumor and proved to be continuous with the lumen of the pylorus. This narrow 
passage diverged from the lumen a short distance in front of the tumor. Two raised folds of epithe- 
lium, parallel with each other and lying longitudinal to the axis of the pylorus, led into the passage. 
The anterior end of the tumor lay 24.5 cm. back of stomach. It was about 9 cm. in length and 2.6 cm. 
in diameter at its anterior end, its posterior end about 9 cm. in front of the entrance of the bile duct. 
These dimensions include the mucous membrane, which was pushed into the lumen by the developing 
tumor. The anterior end was the larger, and the diameter grew gradually less to the posterior end, 
which terminated in a blunt point. The passage, which remained open, was very narrow, and its epithe- 
lium had a different appearance from that of the lumen, both before and behind the tumor. 
In the shark examined on August 19 a similar tumor was found about midway of the length of 
the pylorus, also with a narrow passage beside it. The main lumen was also interrupted at other 
points. I find no mention of such structures in notes made in former years on examinations of this 
shark, and have no recollection of seeing anything like them before. 
