106 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
vagina in M/. ijvmae at least resembles very closely that 
which I have described above, it is small, lateral and 
unpaired, and opens on the left side. The testes are three 
in number, but are very closely apposed to each other, and 
a single vas efferens leaves the compound organ from the 
left anterior lobe. There are indications that the single 
testis of the Port Erin worm was formerly compound, for 
incomplete partitions penetrate into it. The follicles of 
the vitellarium are more numerous. It is possible that 
such differences as that between the testes and vitellaria 
may be of specific value only, but so far as the present 
classification of the Monogenetic trematodes goes one 
must regard the character of the posterior sucker as of 
generic value. In short, the nearest known genus to the 
form now being described is Monocotyle, but the approxi- 
mation is not close enough to justify us in so referring it. 
I propose, then, the name Paracotyle caniculae for 
the Trematode described above, and regard it as the type 
of a new genus and species. 
Paracotyle, gen. nov. 
One anterior sucker; posterior sucker small, and 
without radial ridges or chitinous armature; intestine 
without lateral diverticula; one testis; one vagina on the 
left side; genital aperture in the middle line. 
One cannot help being impressed with the unsatisfac- 
tory state of the classification of the whole group of 
Kctoparasitic Trematodes, but it would, obviously, be a 
futile task to attempt to revise it at the present. When 
one considers how many new Helminths have recently 
been described from tropical and sub-tropical waters,* it 
becomes certain that the group is, as yet, imperfectly 
* For instance by Gotto from Japanese seas, and by Shipley, Hornell 
and Liihe from Ceylon Seas. 
