Habits and structure of Cotylaspis insignis Lerpy. 233 
wall of the mouth-funnel is already highly developed and furnished 
with longitudinal and circular muscle fibres on both sides, and in 
addition with fibres crossing from side to side after the manner of 
radial fibres in the suckers and pharynx, making the active move- 
ments possible and giving it the appearance of a sucker. But it 
is not a true sucker, since there is no limiting membrane upon it, and 
it thus cannot be used to prove kinship with the Distomes, as it is 
by BenHAam (1901) in Lanxester’s Treatise of Zoology. There is 
a long prepharynx reaching from the pharynx to the mouth funnel, 
much longer than in the adult. The pharynx is fully developed. 
There is at this time no oesophagus, the intestine (Fig. 75) directly 
following the pharynx. Certain cells condensing around the anterior 
end of the intestine can be seen in sections, which I regard as the 
beginnings of the oesophageal glands, and I suppose that the 
oesophagus is formed later by the loss of epithelium from the front 
end of the intestine, in favor of which view I would cite the 
epithelial appearance of portions of the cuticle in the adult, already 
referred to. The intestine is fully formed, its epithelium is made 
up of tall cells independent except at their bases and staining more 
deeply at the base. There is a distinct longitudinal coat and a 
more scanty circular coat. 
There are two entirely independent excretory pores and biadders 
(Fig. 75, 81), a feature found in cercaria and rediae (BENHAM, 1901, 
p. 84), and favoring the idea that the Aspidobothridae are sexually 
mature redias originally suggested I believe by Leuckarr. The 
pores were closed by means of a sphincter muscle they were poly- 
gonal when open, and one three angled and the other four angled 
when closed. A close watch of the living animal convinced me 
that the bladders do not contract when discharging as they do in 
the adult, but at intervals of about thirty seconds the pores dilate 
with a gentle movement and after reaching a maximum contract 
again. Small particles could be seen escaping while the pores were 
en The pores contract in unison, one showed a tendency to open 
slightly in advance of the other, occasionally they contracted alter- 
nately. A lumpy concretionary mass was seen in one of the bladders 
but no material was seen in the collecting vessels. The vessels of 
the system are much as in the adult. There is from the bladder 
a long non-ciliated collecting vessel which on the level of the 
anterior end of the pharynx bends backward on itself and runs 
toward the posterior end. This recurrent vessel is ciliated, it gives 
