Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 71. (Budapest 1979)

Varga, A.: On the genus Hygromia Risso, 1826 (Gastropoda, Helicidae)

der Umgängenzahl und mit der Entfernung von der Naht zu. Embryonalschale fein gekörnelt, ohne Schüppchen. Farbe hornbrauen, an der Peripherie meist mit einer helleren Binde. Schale etwas durchscheinend. Masse des Holotypus". 4,60 : 6,05 mm. Genitalen. Penis gedrungen spindelförmig, Epiphallus länglich walzenförmig, etwa 2mal länger als der Penis. Flagellum lang, dünn, am Ende zugespitz, so lang wie der Epiphallus. Vas deferens lang. Zwei etwa gleich grosse Bursae hastae sind vorhanden, die nebeneinander asymetrisch an der einem Seite der Vagina angebracht sind. Die innere Bursa ist leer, die äussere mit einem kurzen (0,8 mm), schnell verjüngenden Pfeil versehen. Es gibt vier Glandulae mucosae, jede fast der gesamten Länge nach in zwei Äste gespalten. Bursa copulatrix oval oder kuelenförmig, mit langem, meist gewundenem Stiel." Shell and its surface structure are depicted in Figs. 7-9 and 39-41. Surface between the scales are smooth. — Penis having a smooth surface and a thin wall is almost completely filled by the papilla sparing only the proximal third part (Fig. 22). It is elongated (three times longer than its width) becoming gradually sharp toward the tip which third is covered by an unusual umbrellate membrane cap (Fig. 25). The inner structure of the papilla shows a gradual narrowing and the ring-like swelling with the three long muscle bundles leaving it in apical direction can also be seen (Type B, Fig. 26). Penis retractor muscle attached to the epiphallus closer than in transsylvanica and deubeli (Fig. 22). In vertical section the swollen wrinkles significant for the terminal part of the epiphallus appear already at the attachment of the retractor muscle (Type D, Fig. 26). The previous two species have only regular ribs over the respective surface (Type C, Fig. 14). The central cavity of the bursa hasta cannot be clearly distnguished from the vaginal space in vertical section. The empty inner bursa enters the vagina in contrast with transsylvanica and deubeli (directly connected with the central cavity). The two bursae are almost of the same volume. Inside the inner bursa, which is empty, a characteristic constriction can be observed around the attachment. About two-thirds of the telum are covered by the papilla filling the free space within the external hasta and its tip reaches the vaginal region. Vagina volume is about twice as large as that of the bursa hasta. Material examined : Hygromia transsylvanica (WEST.): Hungary, Mátra Mts., Mézeskút, N from Ágasvár, leg. VARGA, 26. 4. 1975 (Figs. 1-3, 10-14, 27-30). — H. deubeli (Kim.): Roumania, Gîrbova Mts. near Busteni, stream valley, leg. VARGA, 1971 (Figs. 4-6, 15-21, 31-38). — H. kovácsi VARGA et PINTÉR: Hungary, Com. Békés, Marói-wood at Doboz, leg. DR. KOVÁCS, 14. 5. 1971 (Figs. 7-9, 22-26, 39-41). Although the three species examined show significant anatomical differences these do not seem to be sufficient for drawing clear subgeneral boundaries. Dealing with Hygromia species a comparative volumetric analysis of papilla penis, vagina and bursa hasta are decisive since these organs form a functional unit. That is why some evolutionary trends can be followed even on the basis of this volumetric assay while neglectiny details being of particular interest only. In the cases described a small papilla and vagina is balanced by a large bursa hasta (transsylvanica and deubeli) and vice versa (kovácsi). Comparison of the internal (BH 2) and the external bursa (BH 1) proved to be interesting resulting in the following volume ratios 1:1, 1:4 and 1 : 7 at H. kovácsi, transsylvanica and deubeli, respectively. It is of importance to notice that the internal bursa — penis attanchment at kovácsi shows similarities to H. cinctella (Hygromia s. str.) rather than to transsylvanica or deubeli. The volume ratio of the internal and the external bursa as well as the entrance of the internal bursa represent a certain evolutionary stage. It is a question of further studies wether these anatomical bases of a supposed subgeneric division will be conformed or excluded in the light of the results to be obtained by anatomical analysis of several Hygromia species. Acknowledgement — I should like to thank DR. GY. KOVÁCS (Békéscsaba) for providing samples of Hygromia kovácsi, DR. E. KROLOPP (Hungarian State Geological Institute, Budapest) for the SEM analysis and MR. L. PINTÉR (Zoological Department, Hungarian Natural History Museum, Budapest) for the valuable cooperation. Figs. 10-14. Hygromia transsylvanica (WESTERLUND), genital apparatus. — Fig. 15-21. Hygromia deubeli (KIMAKOWICZ), genital apparatus. — Figs. 22-26. Hygromia kovácsi VARGA et PINTÉR, genital apparatus