W. Nicoll 
345 
pressed against each other. They may be separated by a small space 
occupied to some extent by yolk-glands. They are elongated oval in 
shape and of moderate size, the dimensions being 0'20 x 0 - 18 mm. In 
living specimens the outline is usually slightly crenated but this 
disappears on preservation. The post-testicular space is about {th of 
the body-length or equal to twice the length of a testis. 
The terminal part of the male reproductive organs consists of 
a muscular cirrus-pouch, containing a simple vesicula seminalis, pars 
prostatica and ductus ejaculatorius. In addition there is a vesicula 
seminalis externa, lying free in the parenchyma outside the cirrus- 
pouch and connected with the internal seminal vesicle by a short duct. 
It is sac-like, elongated and a little larger than the internal vesicle. 
It usually lies immediate^ behind the cirrus-pouch. The internal 
vesicula seminalis is small and almost globular. It opens directly 
into the pars prostatica, which is also somewhat globular. The ductus 
ejaculatorius traverses the remaining part of the cirrus-pouch. It is 
usually slightly convoluted and of nearly uniform calibre but sometimes 
it appears almost straight. No spines are present in it and I have 
never seen it exserted. The cirrus-pouch extends behind the ventral 
sucker for a distance rather greater than the diameter of the sucker. 
The ductus opens into a comparatively large genital sinus, which is 
constantly oval in shape and lies on the left anterior border of the 
ventral sucker. Its representation by Miss Lebour on the right side is 
apparently an oversight. 
The ovary is situated immediately in front of the anterior testis and 
may be contiguous with it or separated by a short distance. It is dis¬ 
placed from the middle line slightly to the right side and is considerably 
smaller than either testis. It is almost heart-shaped in outline, the 
apex being directed towards the middle line and from it the oviduct 
issues. The shell-gland complex is of normal type, the oviduct, yolk- 
duct and receptaculum seminis all opening into the proximal end of the 
ootype, and from the junction Laurer’s canal is given off. The ootype 
is short and the shell-gland is diffuse. The receptaculum seminis lies 
to the left of and somewhat dorsal to and behind the ovary. Usually 
it is small and pear-shaped but occasionally it is found greatly distended 
and almost globular. 
The yolk-reservoir lies between the ovary and the receptaculum 
seminis. The yolk-glands are dense but somewhat circumscribed. 
They fill the whole of the post-testicular space, uniting there across 
the middle line, and extend forward along the sides of the body to the 
