Some Trematodes in South African Anura. 
197 
tale ; in Australia by three species of Mesocoelium, viz. Mesocoelium mesem- 
brinum (Johnston), Mesocoelium megaloon (Johnston), and Mesocoelium 
oligoon (Johnston) ; in Asia by M. sociale ; and the form I have prelimi- 
narily described from the gall-bladder of Xenopus laevis may turn out to 
be the South African representative of the Brachycoelinae. 
The Pleurogenetinae, occurring in the anterior part of the intestine, 
are represented in Europe by three genera (Prosotocus, Pleurogenes, and 
Brandesia), comprising between them seven species ; in America by 
Loxogenes arcanum, in Asia by Pleurogenes gastroporus and P. sphaericus, 
and in Australia by P. freycineti and P. solus. Halipegus ovocaudatus > 
occurring in the buccal cavity of European frogs, is also represented in 
South Africa ; in North America represented by H. occidalis ; in South 
America by H. dubius ; and in Asia by H. longispina — all living in similar 
situations ; but, up to the present, no representatives of this fluke have 
been found in Australia. 
Diplodiscus subclavatus in the rectum of European and South African 
frogs is represented in America by D. temperatus, and in Australia by two 
species of Diplodiscus. The European Polystomun integerrimum in the 
bladder of frogs does not seem to be represented in America in frogs, but 
three species (P. coronation Leidy, P. hassalli Goto, and P. oblongum 
R. Wright) occur there in the bladders of Chelonians ; in Australia this 
heterocotylean genus is represented by Polystomum bulliensi Johnston, and 
in South Africa by the European species. No representatives of Diplodiscus 
nor Polystomum have yet been described from Asia. The American 
Cephalogonimus americanus in the intestine of frogs may be represented 
in the Old World by C. lenoiri Poir. The genus Ganeo, described by Klein 
from the Indian Rana hexadactyla, seems to stand alone, unrepresented in 
any other region. Likewise the " species inquirenda," belonging to the 
genus Heterolope, from the body-cavity of Xenopus laevis, referred to above, 
seems to be unrepresented in the frogs of other zoo-geographical regions. 
It is a remarkable fact that, of the six species of flukes described from 
frogs inhabiting Southern Asia, four of them appear to find their nearest 
relatives in flukes from Australian frogs. Mesocoelium sociale Liihe is 
certainly more closely related to the Australian species of Mesocoelium than 
to Brachycoelium crassicolle R., its European, or B. hospitale Stafford, its 
American representative. Pneumonoeces caprystis Klein has been shown 
(Johnston, loc. cit., p. 325) to be more nearly related to P. australis than 
to any other European or American species of this genus, and the Asiatic 
Pleurogenes gastroporus and P. sphaericus and the Australian P. freycineti 
and P. solus have likewise been shown to be more nearly related to one 
another than any of them are to the American or European Pleurogenetines. 
The South African group, on the other hand, is certainly directly related to 
