W. Nicoll 
351 
rhynchus (or rostellum) may be protruded like a small button, or re¬ 
tracted. In the latter case a shallow sucker-like depression is formed. 
The rhynchus is of simple, almost ovoid shape and its diameter is nearly 
twice its depth; it measures 027 x 015 mm. The mouth is situated 
little more than one quarter of the body length from the posterior end. 
The pharynx is flat and circular with a diameter of 0T4 mm. The 
intestine is a simple sac, extending forward from the mouth but not 
reaching the centre of the body. The excretory vesicle extends from 
the posterior end of the body as far forward as the level of the anterior 
testis, i.e. a short distance in front of the pharynx. It is a simple sac. 
The testes are somewhat variable in position. They are of longi¬ 
tudinally oval shape and situated one on each side of the pharynx. The 
left testis is always in advance and its most usual position is on the 
level of the anterior border of the pharynx, while the right testis lies 
on the level of the posterior border of the pharynx. They vary about 
these positions, occasionally approximating the same level, but they are 
never absolutely symmetrical. Their dimensions are 0'26 x 0'20 mm. 
The cirrus-pouch is thick and of moderate length, extending forward to 
the posterior border of the left testis or to about a third of the body 
length from the posterior end. It thus extends a little in front of the 
pharynx, but occasionally just reaches the centre of the latter. It is 
invariably directed towards the left side of the body. An oval vesicula 
seminalis of medium size is situated outside the distal end of the cirrus- 
pouch and overlying it. It is connected with the pars prostatica by 
a narrower portion lying within the cirrus-pouch. The genital aperture 
is near the posterior end of the body. 
The ovary lies on the right side almost exactly on the level of the 
middle of the body. It is thus a little further forward than the left 
testis. It is longitudinally oval in shape and not much smaller than the 
testes. The yolk-glands form a very symmetrical arc in the anterior 
part of the body. The transverse portion of this arc crosses the body 
about 04 mm. from the anterior end ; the lateral portions extend back 
along each side to near the middle of the body, i.e. to near the level of 
the ovary. The follicles are large, and regularly disposed. Alternate 
follicles are situated on either side of the yolk-duct. The right yolk 
duct passes immediately in front of the ovary towards the centre of the 
body but the left duct has a longer course. It passes inwards in front 
of the left testis, crosses the intestine, then turns forwards to join the 
other at the level of the ovary. A receptaculum seminis is absent but 
Laurer’s canal is present. The uterus is of great length and is thrown 
