Two well developed folds are a characteristic feature of the prostate structure in Lymnaea (Lymnaea) vulnerata Küst. A rare case of three folds in the terminal part of this gland is described and illustrated.
Tentacle regeneration in Planorbarius corneus (L.) and Cepaea hortensis (O. F. Müll.) is found to depend on the extent of injury and the season; the regeneration time is longer in the stylommatophoran Cepaea than in the basommatophoran Planorbarius.
Three types of columella structure have been distinguished in shells of selected snail species (Laciniaria plicata (Drap.), Chondrula tridens (O. F. Müll.), Cepaea vindobonensis (Fér.), Helix lutescens (Rossm.), Viviparus contectus (Millet), V. viviparus (L.), Helicella obvia (Menke) and Planorbarius corneus (L.)); they are correlated with the way of coiling, growth and convexity of whorls.
The pneumostomes in Helix pomatia Linnaeus, 1758 and H. lutescens Rossmässler, 1837 are built in a similar way, but differ in the shape of the disc between the two pneumostome lobes, thus providing another diagnostically useful character.