Vallonia astoma O. Boettger, 1909, described from the Durmitor mountains in Crna Gora, Yugoslavia, is known from the western parts of the Balkan Peninsula between Albania in the south and the Karawanken mountains in Austria in the north (Gittenberger, 1967, s.n. Spelaeodiscus astoma). The same species is found in Italy, from where it was first reported s.n. Pleuropunctum micropleuros (Paget) by Giusti (1969). The species under discussion has been dissected and is now considered to belong to the genus Planogyra Morse, 1864, hitherto thought to be represented by two Nearctic forms only. The closely related genus Vallonia differs distinctly from Planogyra in the microsculpture of the shell, illustrated here by some SEM-photographs. The few available anatomical data on Vallonia and Planogyra do not indicate important differences in the structure of the genital apparatus. Spelaeodiscus on the contrary differs markedly in this respect. The real Pleuropunctum micropleuros belongs to the Endodontidae as has been proved by dissection of some specimens. The SEM-photographs of Vallonia costata (figs. 9-11), furnished by the Field Museum of Natural History through the courtesy of Dr. Alan Solem, were prepared with the support of National Science Foundation Grant GB-6779 to Dr. Solem.