64 
Genus — Onchocolyle (Diesing). 
Onchocotyle appendiculata (Kuhn). (Plate V., figs. 9 — 12.) 
Taschenberg, E. 0., " Weitere Beitrage zur Kenntniss ectopara- 
sitiscber marines Treinatoden." Festschrift zur Feier des Hundert- 
jiibrigen Bestebens der Naturforschenden Gesellschaft in Halle, 
1879, page 27. 
I found two examples of this worm on the gills of the Picked 
Dogfish (January). T. Scott* records it from the Grey Skate and 
Thornback Skate from Aberdeen, and A. Scott f records it from the 
Lancashire coast from various ejasmobranch fishes. 
The worm is pale yellowish, with a brown intestine and vitel- 
laria. The body is very flat, long, and narrow ; length 8 mm., 
breadth 1-8 mm. Posteriorly it bears an almost circular disc 
bearing six suckers and a curious median appendage sticking out 
dorsally. The suckers each bear a chitinous semi-circular arma- 
ture, and the posterior appendage bears two oval suckers and two 
very small chitinous spines of a similar shape to those on the 
peduncle of Plectanocotyle caudata (see above). Strong muscle 
fibres go to the suckers and peduncle. The oral sucker measures 
060 mm. across, and is rather broader than long, and flattened 
anteriorly. It leads to a pharynx, 020 mm. long, and this gives 
off an oesophagus of about the same length. The intestinal lobes 
are much swollen and very irregular, and full of brown contents. 
They enter the posterior disc and unite about halfway down it, 
sending off a shoot into the posterior appendage, and continuing 
into the posterior part of the disc. The vitellaria follow the 
intestinal lobes for the whole of their course, filling up the sides 
of the body and obscuring most of the other organs. The testes 
are a group of round masses occupying the posterior part of the 
body from just in front of the posterior union of the intestinal 
lobes to beyond the centre of the body. I was not able to see the 
vasa deferentia, but these, according to Taschenberg, are two thin 
ducts uniting in front of the ovary in a single thicker duct, which 
winding in transverse loops ends in the cirrus sac opening anteriorly 
just below the fork of the intestine. No seminal vesicle is present. 
The ovary is a lobed mass just in front of the testes, giving off, 
according to Taschenberg, an oviduct which almost immediately 
leads to a receptaculum seminis ; from this the oviduct runs as a 
* Scott, T., "Nineteenth Annual Report." Op. cit., page 151. 
t Scott, A., " Rome Additions to the Fauna of Liverpool Bay." Traua. Liverpool Biol. 
Soc, vol. XV., 1901, page 344; and " Some Parasites found on Fishes, etc." Op. cit., page 36 . 
