Differentiation of subfossil populations of snails from Vistulian loesses of Southern Poland

Mollusc shells are commonly noted from loesses and loess-like deposits. The typical feature of loessial malaconecrocoenozes is their abundance with relatively low number of species. The strength of specimens, which are different by their nature themselves, has allocated many low-level taxons within particular species. In many cases, the bases for such allocation are metric features of shells. The author has tried to decide the taxonomic question of the most important and the most frequent species which occur in loess deposits i.e., Succinea oblonga, Pupilla muscorum, Pupilla loessica, Trichia hispida, and Arianta arbustorum.