386 
<. J. JOHXSTOX. 
anterior edge of the ventral sucker in three or four S-shaped 
bends, and opens into the genital sinus alongside the male 
opening. Idie eggs are never numerous. The yolk-glands, 
consisting of small rounded follicles 0’048 mm. in diameter, 
are very richly developed. In front they reach the level of 
the anterior border of the ventral sucker and are in this 
region confined to the lateral pai-ts of the body. Passing 
backwards they gradually extend inwards to the middle line, 
so that in the posterior half of the animal they fill up the 
whole field, extending right across the body and back to the 
extreme posterior end. The eggs are thin-shelled, light in 
colour, 0’073-0'076 mm. long by 0‘046 mm. wide. 
This species differs from P. polyorchis Stossich in its 
larger size, in the absence of spines, in its much larger oral 
sucker, in the smaller number of testes, and in its spherical 
ovary. 
Fam. Steringophoridte. 
S teringo trema pulchrum sp. n. (Figs. 12,41 and 42). 
Diagnosis. — Middle-sized worms, almost lanceolate in 
shape. Ventral sucker in front of the middle of the 
body. Ratio of the oral to the ventral sucker 1 : P8. Pharynx 
more than half as large as the oral sucker; oesophagus 
very short; intestinal limbs reaching to near the posterior 
end. Excretory vesicle V-shaped, the limbs reaching the 
level of the oral sucker in front. Testes near the middle of 
the body; ovary in front of right testis; Laurer’s canal 
present, but no receptaculum seminis ; loops of the uterus 
confined to the space between the intestinal limbs; yolk- 
glands lateral to the intestinal limbs, not reaching the 
ventral sucker in front; eggs 0*043-0’048 mm. long by 
0'032-0‘035 mm. broad, thick shelled. 
In the gullet of the black toadfish,^ and the spotted 
toadfish.^ 
^ There seems to be some doubt whether these two fishes represent 
distinct species or colour varieties of the same species, Tetraodon 
hispidus. 
