CHAPTER V 



OCCURRENCE OF MONOGENETIC TREMATODES AMONG 

 AMPHIBIA AND REPTIUA 



As has already been mentioned, monogenetic trematodes are p. 279 



also encountered on amphibians and reptiles. They are representatives 

 of 2 families --Polystomatidae and Sphyranuridae. If we accept the system 

 of the first family proposed by Price (Price, 1939), which basically reflects 

 the natural relations, separating however, Sphyranura into a special family 

 (see page 401 ), then five genera (Polystonna, Parapolystonaa, Diplorchis, 

 Eupoly stoma, and Sphyranura) are encountered annoug Amphibia and three 

 (Poly stomoides, Polystomoidella, and Neopolystoma) among reptiles. 



Of the five genera under discussion which are encountered 

 among the Amphibia, one (Sphyranura) parasitizes caudate amphibians, 

 and the remaining four-- acaudate. The representatives offtie genus 

 Sphyranura are encountered on Proteidae (in a single species--Necturus 

 maculosus Raf. ) and Salamandridae (Eurycea tynerensis Moore and Hughes), 

 and on the first family (species)--three species, while in the second--one; 

 in each case each species of parasite is encountered only on one species of 

 host. Both families of caudate amphibians are undoubtedly closely related. 



As hosts of the genus Polystoma are representatives of the 

 genera Rana (with 2 species of Polystoma), Bufo (2 to 1 species), Hyla 

 (4 species), Rhacophorus (1 species), and Xenopus (1 species). All the 

 described species of Polystoma are encountered either on one species of 

 host or on several related to one genus. An exception is P. integerrimum 

 Froelich, which was authentically discovered in Rana temporaria, R, arvalis, 

 R. agilis, R. esculenta, and Bufo viridis. As a whole the genus Polystoma 



1 



The indications of the presence of this species on other amphibians is 

 erroneous. 



is encountered in the representatives of four families related to the sub- 

 orders of raniformids, bufoniformids,and bonabiniformids. If the first 

 two suborders are undoubtedly close, then the bombiniformids and especially 

 Pipidae, to which Xenopus laevis Daud. --the host of P. xenopi Price is 

 related, are rather sufficiently removed from them (Terentiev, 1950). In 

 becoming fanniliar with the morphology of P. xenopi we see that this species 

 sharply differs from all other species of Polystoma. These differences can 

 be summed up as follows. In the first place the intestinal trunks in P. 

 xenopi do not form conamissures among themselves and do not merge at 

 the posterior end. If the first indication, that is the absence cf commissures 

 between the intestinal trunks, is encountered among certain species of 



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