Habits and structure of Cotylaspis insignis Lerpy. 213 
of the pharynx in front and with the epithelium of the intestine 
behind. In living animals the tall cells of the intestine are at 
times by the contractions of the body pushed up into the cavity of 
the oesophagus. The cuticle exhibits also certain slender elongate 
structures smaller than the intestinal cells but of much the same 
form, which accompany the intestinal cells in their swaying move- 
ments. These are not always present and do not show in the 
preparation from which Fig. 18 was taken. They appear to be the 
remains of cells which have been cuticularized, and in addition to 
the position of the cuticle favor the belief that the cuticle in this 
part of the animal is a modification of the epithelium. Prarr 
(1898) thinks that the cuticle is a modification of the layer under- 
lying the epithelium as in the appendix of Apoblema he finds it 
runing under the epithelium. My sections do not permit this inter- 
pretation, the cuticle not underlying the epithelium but being 
directly continuous with it. I may say here that I have found a 
somewhat similar structure in the oesophagus of Clinostomum, where 
long slender processes of the cuticle are present, of which an account 
will appear in an article on that animal. It is only in form that 
these oesophageal structures in Cotylaspis show resemblance to 
epithelium, there are no nuclei or remnants of them to be found in 
the cuticle. 
There are numerous unicellular glands in the parenchyma sur- 
rounding the oesophagus, which differ from the parenchyma glands 
in being smaller, and in staining well. I have not succeeded in 
tracing ducts from these cells, and do not know whether they dis- 
charge into the oesophagus or farther forward into or in front of 
the pharynx. VOoELTZkow (1888) and Srarrorp (1896) describe 
similar structures as salivary glands. In Aspidogaster, however, the 
cells lie on the sides of the pharynx and discharge in front of it. 
Glands of this sort are common in the trematodes and terminate 
variously. In Polystomum (ZELLER 1872) they are postpharyngal in 
position, and, according to BRAUN, discharge into the pharynx 
posteriorly. WALTER (1883) describes two species of Monostomum. 
In M. proteus they are in a diffused mass surrounding the pharynx 
and intestine, while in M. reticulare there is a single compact mass 
on each side which discharges into the hinder part of the pharynx. 
In Distomum palliatum (Looss 1885) these glands lie in a position 
exactly the same as in Cotylaspis. 
The intestine, as in the rest of the family, is entirely simple; 
