AKT. 17 PARASITES OF AMPHIBIA AND EEPTILIA HAEWOOD 5 



two my specimens should be referred. Comparison with some speci- 

 mens of H. haematohiuvi, which were kindly supplied by Doctor 

 Stunkard, showed that my forms are not identical with these. They 

 differ in having more closelj^ packed and more deeply lobed testes, 

 which are the characters that Stunkard pointed out as essential dif- 

 ferences between his H. haemaiohium, and the specimen that was 

 sent to him by MacCallum as representative of H. chelydrae. From 

 MacCallum's description it is not possible to differentiate the two 

 species. My specimens are, therefore, referred to Henotosoma 

 chelydrae- 



Family PARAMPHISTOMATIDAE (Fischoeder, 1901) Stiles 



and Goldberger, 1910 



Subfamily Diplodiscinae Cohn, 1904 



This subfamily was founded in 1904 by Cohn to include the three 

 genera Diplodiscns^ Ojylsthodiscus^ and Catadiscus. The history of 

 the North American members of this group began somewhat previous 

 to that time, for both Stafford and Leidy had reported the presence of 

 Diplodiscus suhclavafiis in North American frogs. Stafford (1905) 

 separated the North American form from the European and named it 

 Diplodiscus tevijyeratus. No other representatives of this group were 

 described from North America until Chandler (1923) proposed the 

 genus Megalodiscus for a new species that he discovered in the rectum 

 of Atnphiuma m£ans. Millzner (1924) added Megalodiscus rano- 

 philus from the rectum of the common leopard frog to Chandler's 

 genus. Since that time some little doubt has been thrown on the 

 validity of Megalodisciis^ but no thorough discussion of the prob- 

 lem has been forthcoming. Chapin (1926) believed that Megalo- 

 discus ranophilus was identical with Diplodiscus temperatus. Cort 

 (1926) agreed with Chapin, and in addition stated his belief that 

 Megalodiscus should be considered a synonym of Diplodiscus. 

 Hunter (1930) placed Megalodiscus americanus in the genus Diplo- 

 discus. On the other hand, HoU (1928a ) expresses himself as follows : 

 " The writer has not seen any specimens of Megalodiscus., but believes 

 that future work will show that there are a number of species, belong- 

 ing to this group, in North America." Poche (1926) listed Megalo- 

 discus with the Diplodiscinae. Fukui (1929) rejected Megalodiscus., 

 stating that the differences cited are not of generic value. He in- 

 cluded Diplodiscus temperatus., however, with those forms having a 

 single testis in contrast to those having two, and thereby confused the 

 whole group. Neither in my own material nor in any available 

 descriptions have I found any reference to D. temperatus having any 

 tendency whatsoever toward fusion of the testes. 



