VV. Nicoi.L 
37 
by the ductus ejaculatorius. The pars prostatica is indistinct. The 
wall of the cirrus-pouch is extremely thin. 
The testes are situated immediately in front of the ventral sucker, 
with which they are contiguous. They lie symmetrically alongside each 
other, their inner surfaces being in contact. Their shape is somewhat 
peculiar, their posterior borders being hollowed out to fit the convexity 
of the ventral sucker. Their outer surfaces are pressed against the 
intestinal diverticula, while their anterior borders are convex. Their 
dimensions are 0-18 x 0-23 mm. 
Immediately in front of the right testis and contiguous with it lies 
the large ovary. It is roughly oval in outhne and measures 0-16 
X 0-22 mm. Its posterior border is pressed close against the right testis. 
In front of the ovary and alongside the end of the cirrus-pouch lies a 
large globular receptaculum seminis with a diameter of 0-12 mm. The 
yolk glands are lateral and extend from the level of the pharynx to 
the middle of the ventral sucker. They surround the intestinal diverti¬ 
cula, but the majority of the follicles are dorsal. The yolk ducts run 
down the inner side of the diverticula. The uterus occupies the median 
field at the left side of the ovary and cirrus-pouch. The ova are not 
numerous and they measure 0-065-0-07 x 0-03 mm. The vagina is more 
than half the length of the cirrus-pouch and it has a curiously twisted 
course. 
This species is rather an anomaly as a Distome. At first sight it 
appears to be an Amphistome, judging from the position of the ventral 
sucker. The internal anatomy, however, obviously shows that it 
belongs to the former and not the latter class. Its systematic position 
among the Distomata must be left for the future to decide. 
Genus Gyliauchen n. g, 
Gyliauchen tarachod.es n. sp. 
(Plate V, fig. 10.) 
A considerable number of specimens of this remarkable parasite 
were obtained from the intestine of a pilot fish {Tachysurus n. sp.). 
It is a small, elongated, moderately plump form, measuring 2-6-3-5 mm. 
in length. It is somewhat pointed at both ends, more so at the 
anterior than at the posterior end. The greatest breadth is about 
one-third of the length and occurs just behind the middle of the body. 
There are no cuticular spines and the cuticle is smooth. 
