Polystoma and also among other Pclystomatidae of acaudate amphibians, 



the second on the other hand, is characteristic only for this particular 



species. Thus, if one is to consider the data of Yamaguti (Yamaguti, 1936) 



as correct, then even among all the Diplorchis the intestinal branches merge p, 280 



at the end. In the second place the uterus is absent among P. xenopi and there 



is only an obtype containing one egg just as among neotenic forms of 



Polystoma and the representatives of Polystomatidae among reptiles. No 



(other, nobis) species of this family parasitizing Anura (we are speaking 



here about "normal" and not neotenic forms) has ftiis feature. Generally. 



this group expresses the tendency toward elongation of the uterus, which 



is connected undoubtedly Nvith the peculiarities of the life cycle, particularly 



with the short period of "expedient" egg -laying (see page 121 ). Besides these 



differences there is also one less meaningful: Thus the number of chitinous 



hooks of the sex armature of P. xenopi is 14 whereas among the remaining 



species of Polystoma they do not exceed 10; however, this undoubtedly is 



only a species character. A very important indication would have been the 



absence of vaginal ducts, which possibly differentiates P, xenopi from other 



species, but we cannot speak with certainty of this because the species was 



poorly studied ana apparently is known so far only from one specimen 



(Price, 1943c). We can say with certainty that P. xenopi differs from 



representatives of the genus Polystoma with various distinguishing features 



which have a primitive character and, in this connection, it would be quite 



lawful to separate this species into a special genus Protopoly stoma gen , nov ., 



containing, so far one species- -P. xenopi (Price, 1943) Bychowsky comb . 



nov. parasitizing Pipidae. 



Representatives of the genus Diplorchis are encountered, one 

 species each in one species of the host- -two species in Ranidae (in Rana 

 species), and two in Pdobatidae (in Scaphiopus sp. ). Both families are 

 rel?ted to different suborders which are not very close to each other. 



The genus Eupolystoma is described from Rana species. 



Finally the genus Parapolystoma is found only on representatives 

 of the bufoniformid group; one species is known from tv^^o species of Hyla 

 (Hylidae) and the other apparently from Bufonidae although this has not been 

 firmly established (the worms wers found in the free conditioii in the pond 

 where the toads of the genus Bufo lived). 



Polystomatidae found in reptiles are discovered only on tartles 

 connected with the water medium. The genus Polys t omoides , containing 

 nine described species, is indicated from four families --Testudinidae, 

 Cheloniidae, Chelidridae, and Trionychidae, and for the second of them"" 

 erroneously, as we shall see later. All the species are indicated as en- 

 countered either on one host or on representatives of one genus. Two 

 species, P. ocellatus (Rudolphi) and F. coronatus (Leidy), form an ex- 

 ception. Thus, the first species is known from Emys orbicularis (L. ) 



321 



