STUDIES ON THE DIGENETIC TREMATODES. 437 
filled up with the hair-like processes of the epithelial cells. 
Moreover, its function seems to have been undertaken by the 
initial part of the uterus, which in every specimen is packed 
full of sperms (receptaculum seminis uterinum). Almost 
immediately beyond the above-described turning of the ovi- 
duct Laurer’s canal arises. It has a peculiar and almost 
constant course. It passes first towards the dorsal surface, 
bending slightly to the left, but after traversing half the 
distance it turns suddenly at right angles and runs posteriorly 
parallel to the dorsal surface for a considerable distance, 
describing at the same time almost a complete semi-circle 
with its convexity towards the right. It then again turns 
abruptly at a right angle and passes in a more or less direct 
course towards the dorsal surface, where it opens almost in 
the middle line on the level of the anterior border of the 
anterior testis or a little further forwards. Its diameter is 
about (025 mm. 
From the origin of Laurer’s canal the oviduct proceeds 
on its way towards the ootype, running almost parallel to the 
surface of the ovary. Just before entering the ootype it 
receives the common yolk-duct, which passes forwards in a 
rather sinuous course from a small reservoir lying a little in 
front of the anterior testis and almost midway between the 
ovary and the dorsal surface. The ootype, which is situated 
dorsal to the left end of the ovary, bends forwards and 
dorsally to pass into the uterus. The ootype is wider 
(diameter ‘033 mm.) than the oviduct and the uterus is still 
wider. The shell-gland is of large size. It does not invest 
the ootype closely, but its cells are diffusely scattered in the 
surrounding parts and communicate with the ootype by means 
of long ducts. They are most numerous around the oviduct 
and common yolk-duct. The histological structure of the 
shell-gland complex conforms to the usual type. The whole 
course of the oviduct is lined by a thick ciliated epithelium. 
The cilia are fairly long and are directed away from the 
ovary. The receptaculum seminis is also lined by this ciliated 
epithelium, the cilia of which are so numerous that they 
