Dr. Murai Éva szerk.: Parasitologia Hungarica 19. (Budapest, 1986)
which have a vagina that is shorter by as much as 1/2 of the cirrus sac, or maximum 1/2 of the cirrus sac: P. blanchardi, P. janickii and P. petauristae. Tapeworms which have a vagina longer than 1/2 of the cirrus sac form the most numerous group. In this group the important differentiating criterion is the distribution of the testes: (1) the testes distributed both in the aporal and poral part of the segments, or (2) the testes are either exclusively in the aporal part of the segments or predominantly in the aporal part of the segments. Using this differentiating criterion along with knowledge of the character of the seminal receptacle, we have obtained several groups with species that are closely related. Using comments given previously it seems that in the group where the oldest known described species is P. omphalodes, another bona species is P. mascomai, conditionally also P. caucasica. At the same time a synonym of the species P. caucasica seems to be P. microti and P. ki rbyi . A species inquirenda is P. campestris. P. arct ica differs from P. primordialis in the group where it is the oldest described species. It is very hard to distinguish the species P. gracilis and P. kalelai from P. primordialis. These two species differ from each other evidently in the ratio length of vagina: length of cirrus sac. Very numerous is the group where the oldest described species is P. macrocephala . Its synonym seems to be perhaps P. translucida whereas P. bialowiezensis is a nom en nudum. The species P. communis appears to be well distinguishable, P. ondatrae seems to be a bona species as well. P. bairdi and P. neotomae also belong to the group of species which can be easily identified. From this survey it is evident that there are still some other, yet undescribed, species of the Paranoplocephala. Criteria, according to which - in the author's opinion - the hitherto described species of the genus Par anoplocephala can be distinguished, have been included into an identification key. The process of finding further criteria is a completely open matter. ORIENTATION KEY TO THE SPECIES OF THE GENUS PARANOPLOCEPHALA LÜHE, 1910 1. Testes positioned in premature and mature segments differently, scolex about 0.400mm, parasites of mountain - Caucasus - rodents in USSR (Figs 6 and 7) Paranoplocephala montana (Kirschenblat, 1941) Tapeworms with other morphological, metrical and ecological marks 2 2. Vagina shorter than 1/2 of the cirrus sac, or 1/2 of the cirrus sac 3 Vagina longer than 1/2 of the cirrus sac 5 3. Testes in aporal half of the segments (Fig. 8) Paranoplocephala blanchardi (Moniez, 1890) Testes in poral and aporal part of segments anteriorly to female gonads 4 4. Cirrus sac only slightly overlapping ventral excretory canal. Parasites of Micrqtus arvalis (Fig. 9) . . .". ~. . P aranoplo cep hala janickii Tenora, Murai et Vaucher, 1985 - Cirrus sac considerably overlapping ventral excretory canal. Parasites of Petaurista l^eucogenys_(Sciuridae) (Fig. 33) Paranoplocephala petauristae (Sawada et Kugi, 1979) 5. Testes mostly in aporal half of segments 6 - Testes in aporal and poral half of segments 11 6. Seminal receptacle oval or spherical (Fig. 10) Paranoplocephala bairdi (Schad, 1953) Species studied personally
