SEKA-FISHERIES LABORATORY. 91 
not seen this condition. The cavity in the pharynx is 
complex in shape, but very usually presents a triradiate 
appearance in horizontal sections of the worm. ‘The 
muscular wall of the pharynx is very complex, and I do 
not propose to describe it here. At the posterior end this 
muscular wall thins out, and the cavity of the pharynx 
becomes continuous with that of the intestine. There is 
no oesophagus, and the pharyngeal lumen is directly 
continuous with that of the part of the alimentary canal 
which crosses the body transversely from behind the one 
excretory vesicle to the other (Pl. I). At the two latter 
places the intestine bends backwards as the two longitu- 
dinal rami. The latter are not straight, but are thrown 
into double S-shaped curves. There are no lateral pouches 
nor diverticula of any kind, and in this respect the species 
here described agrees with Monocotyle, but differs from 
Pseudocotyle. 
The epithelium lning the intestine is represented in 
Pl. II, figs. 3, 4 and 5. It belongs to a type of intestine 
found in the genera Mvrcrocotyle, Aaine, Octocotyle, 
Diclidophora, Hexacotyle, and Octocotyle, as opposed to 
the kind of intestine found in 7ristomum, Hpibdella, 
Monocotyle, Callicotyle, and the Gyrodactylidae,* so that 
this species departs from Monocotyle in this respect, and 
approximates to the Tristomidae. In most Distomes the 
epithelium lining the intestine consists of a continuous 
layer of cells, cubical or cylindrical, resting on a basement 
membrane. In other forms, however, the cells are 
partially isolated from each other, are amoeboid or are 
highly extensile, and have no apparent cell membranes. 
This is the case in the present species, where the intestinal 
wall consists of an irregular layer of ceils resting on a 
*See 8. Gotto, “Studies on the Ecto-parasitic Trematodes of 
Japan.” Journ. Coll. Sci. Imperial University Japan ; Vol. VIII, 
pt. I, p. 58; Tokyo, 1894. 
