W. Nicoll 
371 
of oral sucker 0-24 mm., diameter of ventral sucker 0-42 mm., distance 
of ventral sucker from anterior end 1-15 mm. 
From these figures it appears that the species, on an average, is some¬ 
what more elongated than the original specimen, and that the sucker 
ratio is about 4: 7 instead of 4 : 6. In the original description it was 
stated that the intestinal diverticula terminated a short distance behind 
the ventral sucker. This, however, is not the case, for in a pressed pre¬ 
paration they can be traced, running alongside the yolk glands, to near 
the posterior end of the body. As they are unusually thin-walled and 
obscured, for the greater part of their course, by the dense folds of the 
uterus they are difficult to discover in total mounted preparations. 
The wall of the cirrus-pouch is extremely thin and weak. The pouch 
contains a large bipartite vesicula seminalis which occupies about two- 
fifths of the length of the pouch. The remainder of the pouch is traversed 
by a narrow ductus surrounded by numerous cells, but no distinct pars 
prostatica could be detected. There is, further, no genital sinus, the 
vagina joining the cirrus-pouch close to the genital aperture. The ap¬ 
pearance simulating a sinus in the original specimen was due to a kink 
in the terminal part of the cirrus-pouch. 
SIGMAPERA n. g. 
Sigmapera cincta n. sp. 
(Plate VIII, fig. 2.) 
About thirty specimens of this interesting parasite were collected 
from the intestine of two freshwater turtles {Emydura latisternum). 
They present several features of interest. 
The species is of small size, the largest specimen only slightly ex¬ 
ceeding 1 mm. in length. The body is flattened, delicate and transparent, 
while the shape is elongated with pointed ends. The posterior part is 
generally more expanded than the anterior part, which in some cases 
is greatly attenuated. The cuticle is beset with minute spines, through¬ 
out the anterior two-thirds of the body. 
The specimens were of fairly uniform size, the average length of the 
best extended being T08 mm. The maximum breadth in the posterior- 
half of the body is 0-28 mm. The globular oral sucker has a diameter 
of 0-066 mm., while the inconspicuous ventral sucker measures 0-07 mm. 
The latter lies behind the middle of the body at a distance of 0-65 mm. 
from the anterior end. 
