Dr. Murai Éva szerk.: Parasitologia Hungarica 16. (Budapest, 1983)

3) SKRJABIN (1949) removed the genera Helostomatis and Opisthodiscus from Diplodiscinae and the same was done by YAMAGUTI (1971) Progonimodiscus

, Dermatemytrema, Catadiscus and they raised these genera to subfamily rank. Accordingly, in YAMAGUTI'

s list (1971), which is the latest and most comprehensive of this subfamily, five genera (

Diplodiscus, Catadiscus

, Megalodiscus

, Opisthodiscus and Pseudo- diplodiscus

) were presented. Initial observations suggested that the previous classification of the group did not adequately represent the phylogenetic relationships of its included members. Suprageneric designation (SKRJABIN, 1949; YAMAGUTI, 1971) has sometimes been based on imperfect morphological traits hence, establishing of the subfamilies above, does not seem to be justifiable. After examining the majority of diplodiscids, eight morphotypes were recognized on the basis of the structure of the genital organs, the digestive tract and the fixative organ: 1) those with single testis, vitellaria along the lateral sides, short caeca; 2) those with single testis, vitellaria along the lateral sides, long caeca; 3) those with single testis, vitellaria at only the middle part of lateral sides; 4) those with single testis, vitellaria at zone of the anterior end of caeca, short oesophagus; 5) those with single testis, vitellaria at zone of the end of caeca, long oesophagus; 6) those with single testis, vitellaria at posterior lateral sides, acetabulum with ruffled peduncle; 7) those with two testes, vitellaria lateral along caeca; 8) those with two testes, vitellaria at posterior zone of caeca. Generic status was assigned to each group and their character states indicate that each group constitutes a monophylic taxon. Thus, as a result of the review eight genera were recognized: Australodiscus n. gen., Catadiscus

, Diplodiscus

, Dermatemytrema, Megalodiscus

, Opisthodiscus, Progonimodiscus and Pseudo- diplodiscus. On the basis of the genital organs and the structure of the digestive tract two suprageneric groups can be designated: 1) those with one testis, short caeca, long oesophagus - Diplodiscinae with genera: Australo discus, Catadiscus, Diplodiscus

, Dermatemytrema, Progonimodiscus

, Pseudodiplodiscus; 2) those with two testes, long caeca and short oesophagus - Opisthodiscinae with genera: Me galodiscus, Opisthodiscus. MATERIAL AND METHODS The revision was based on the published material and obtainable specimens: whole mounts of Catadiscus cohni

, C. rodriguesi

, Diplodiscus fischthalicus

, D. lali and sections of D. mehrai

, Dermatemytrema trifoliata

, Megalodiscus americanus

, M. temperatus

, D. subclavatus and Opisthodiscus diplodiscoides were available for examination. Cercariae of D. subclavatus were released from naturally infected snails, Planorbis planorbis for artificial infestations. Green frogs and Viviparus viviparus were infected with metacercariae and they were dissected at definitive intervals. YAMAGUTI (1971) handled the rank and position of the genus Catadiscus controversially^ namely, species of this genus found in amphibian hosts were placed to Diplodiscinae and, at the same time, those being parasites of reptiles were included in a new subfamily Catadiscinae, constructed by himself.