Some Trematodes in South African Anura. 
195 
limbs, and only overlapping the limbs anteriorly. A vesicula seminalis is 
present. The genital aperture is situated between the suckers, nearer to 
the posterior sucker. 
With respect to such external characters as the division of the body 
into a narrow mobile anterior and a broad flattened posterior region, it 
certainly belongs to the Gorgoderinae (cf. Spathidium folium v. Olfers), 
but it differs from them in the presence of a well-developed pharynx, 
short oesophagus, vitellaria confined to the sides, and a poorly developed 
posterior sucker. 
It differs from the Brachycoelinae in respect to pharynx, length of 
intestinal limbs, and position of the vitellaria, but agrees with them in 
respect to the position of ovary and testes and the coils of the uterus con- 
fined to the region behind the testes. It certainly shows affinities with 
both the Gorgoderinae and Brachycoelinae. I am of opinion that it is 
more closely allied to the latter than to the former. 
A Distomid from the Body-cavity of Xenopus laevis belonging to 
the genus Heterolope Looss (sp. inq.). 
This trematode I found in the body-cavity of Xenopus laevis. On one 
occasion I found it under the peritoneum on the outer surface of the 
lungs. The worm measures 9 mm. from end to end, greatest breadth 2 mm. 
It tapers more posteriorly than anteriorly. The suckers are well developed, 
and approach each other. The ovary lies between the testes, which are 
situated one behind the other in the middle line in the posterior region of 
the body. Cirrus-sac, ductus ejaculatorius, and cirrus present ; a vesicula 
seminalis lies outside the cirrus-sac. The genital aperture lies just in 
front of the anterior testes in the posterior region of the body, far 
behind the posterior sucker. The coils of the uterus lie in front of 
the testes. 
So far I have not been able to find a frog-trematode recorded in which 
the genital aperture lies far behind the posterior sucker in the posterior 
region of the body. It undoubtedly belongs to the genus Heterolope 
Looss, or a closely allied genus. 
General Conclusions. — In considering the relationships and distribution 
of the hosts of South African frog-trematodes, one can, it appears to me, 
only arrive at such conclusions as Johnston (14) did with respect to the 
Australian frog-trematodes. The following is a reproduction of his con- 
clusions so modified as to include the South African representatives. 
The occurrence of the trematodes recorded above from South African 
frogs gives a striking illustration of the tendency of helminths to occur in 
faunal groups. That is to say, that helminths found parasitic in any 
