90 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
it is ventral in position, as in Text-fig. 1, but it may 
be situated at the extreme anterior margin of the body, 
as in Pl. I. The opening in the anterior sucker 
leads into a relatively narrow passage, which is the 
vestibule, or pre-pharynx. 



Transverse bart 
Of PrErts 
! 

Vestibule 
Fig. 1. Diagrammatic longitudinal section through anterior part 
of body. 
The posterior sucker is relatively small—-smaller than 
in species of Mfonocotyle, but larger than in Pseudocotyle. 
It is simple; raised up only slightly from the general 
ventral surface; and possesses no radial ridges nor hooks 
of any kind. It is quite terminal in position. 
Alimentary Canal. 
The vestibule expands to form a relatively large 
cavity in the anterior and median part of the body, and 
in this is situated the pharynx. The latter is nearly 
globular in shape being only slightly elongated in a 
transverse direction. It lies, for the most part, freely in 
the vestibule, and only its posterior margin is continuous 
with the membrane lining the latter. Strong muscles are 
inserted in its posterior surface, and originate in the 
dorsal integument behind the pharynx Probably the 
latter can be extended, as a whole, through the vestibule 
and the opening of the anterior sucker, although I have 
