208 Henry Lesrre OsBorx, 
or 1.5 mm to 3.0 mm, his maximum must have been from a living 
and much extended specimen, his minimum is more nearly the size 
of the average of the Chautauqua specimens. According to POoIRIER 
(1886) C. lenoiri is 1.7 mm long and 1.0 mm broad. Cotylaspis is 
thus the smallest genus of the family, Aspidogaster bemg 3.0 mm 
long, Cotylogaster, 10.0 mm long and S#ichocotyle 105 mm long. In 
life the body is quite distinct from the ventral sucker, rising pro- 
minently above it and having its contour complete posteriorly, so 
that it has a form (exclusively of the ventral sucker) much like 
that of some of the Distomids. The huge ventral sucker which 
extends around the body on the sides and behind (Fig. 5) is the 
most prominent external organ. There is no true oral sucker, but 
a very mobile region in front of the pharynx, the mouth funnel, has 
the appearance of one. It is a cavity opening obliquely downward 
and forward, and tapering posteriorly to a low eminence on which 
the mouth, a narrow vertical slit, is situated. There is a low conical 
eminence near the hind end of the body at the summit of which 
the single excretory pore opens. The genital opening is located in 
the middle ventral line of the “neck” a little in advance of the 
margin of the ventral sucker. 
The ventral sucker in the Aspidobotridae is characteristically 
sub-divided into areas, acetabula, of different pattern in each genus. 
The number given by Lerpy in his original description of Colylaspis 
insignis is 29, and this number holds as the usual number for the 
= 
OR, eee RY e 
CAS] CA d a 
Diagram to show the variation in the acetabula of the ventral sucker. A is a 
copy of the posterior end of the mode, from Pl. 13, Fig. 6, the rest are the 
variants found. 
Chautauqua animals. There is as in Fig. 6 a peripheral series of 
twenty acetabula and a central series of nine, so related that each 
one of the median row has one of the peripheral row at each side, 
or we could say that there are three longitudinal rows. There are 
three rows in Cotylogaster and four rows in Aspidogaster. While 
