150 DR. W. NICOLL ON TREMATODE 
usually a slight indentation on either side about the middle of 
their length. Their dimensions are -34x°25mm. The posterior 
testis is a trifle larger than the anterior one. They are very 
close together, but are not quite contiguous. In front they are 
separated from the ovary by a space of -15 mm.; behind them 
the post-testicular space is 1:68 mm. in length. 
The small transversely oval ovary is situated 1:02 mm. 
behind the ventral sucker. It is almost median, and measures 
"15x:21 mm. The yolk-glands are rather restricted in extent. 
On each side they reach the posterior border of the ventral 
sucker ; posteriorly they cease at some distance from the tip of 
the tail. They are for the most part confined to the outer side of 
the intestinal diverticula, and overlap them only to a very slight 
extent. The transverse yolk-ducts cross between the ovary and 
anterior testis. The uterus does not overlap the intestinal 
diverticula, and is confined between the ovary and the ventral 
sucker. The ova are very large, measuring *114—-122 x -069- 
074 mm. 
Family CLINOSTOMIDA. 
10. HARMOTREMA INFECUNDUM, gen. et sp.n. (PI. IV. fig. 10.) 
A considerable number of specimens of this species was ob- 
tained from the intestine of Smyth’s Water-Snake (Grayia 
smythii). It is one of the most remarkable forms in the present 
collection. 
It is a small, rather flat species, white in colour and with the 
edges of the body thrown into irregular wrinkles. The cuticle 
is unarmed. 
Tt is about 2 mm. in length, with a fairly uniform breadth of 
-6 mm. Both ends are slightly pointed. The suckers are small 
and feeble, the oral having a diameter of -13 mm. and the 
ventral 08 x ‘10 mm. The latter lies °8 mm. from the anterior 
end. : ‘Ei 
There is no prepharynx; the pharynx measures ‘06 x ‘04 mm., 
and the csophagus is about the same length as the pharynx. 
The intestinal diverticula are wide and sinuous, and reach the 
posterior end of the body. Behind the ventral sucker they 
usually bend inwards before passing out again to make room for 
the genital glands. At their termination they again turn in 
towards the middle line. 
The genital aperture is situated on the left side of the body, 
internal to the intestinal diverticulum and almost midway 
between the ventral sucker and the posterior end of the body. 
The curious thin-walled cirrus-pouch stretches forwards from 
the genital aperture in a zigzag or sinuous fashion, and its 
proximal end lies against the right intestinal diverticulum. It 
contains a bipartite vesicula seminalis, of which the proximal 
part is oval and the distal elongated. There is a moderately 
