Caucasocressa Hesse, 1921

Hausdorf, Bernhard, 2003, Revision of the genus Caucasocressa from the eastern Pontic Region (Gastropoda: Hygromiidae), Journal of Natural History 37 (21), pp. 2627-2646 : 2628

Genus Caucasocressa Hesse, 1921

Caucasocressa Hesse, 1921: 63 . Type species (by original designation): Helix Joannis Mortillet, 1854 .

Diagnosis. Shell (figures 3–21) depressed conical to disc-like; with four to six convex whorls; teleoconch with wrinkled growth ridges, in some species with a granular sculpture, in some with hairs; brownish corneus or whitish, often with one or two brownish bands; body whorl rounded; aperture almost circular or elliptical; upper insertion of the peristome slightly or distinctly descending; peristome more or less sharp, not or slightly expanded, with a whitish internal rib; umbilicus narrow or wide, taking about 7–25% of the shell breadth.

Genitalia (figure 1) without dart apparatus. Penial papilla perforated by the sperm duct. Lumen of the penial papilla with folds. The right ommatophoral retractor muscle passes between penis and vagina.

Remarks. The genitalia of Caucasocressa (figure 1) are simplified by the complete loss of the dart apparatus. The proportions of the copulatory organs are the only species-specific features of the genitalia. Therefore, the genitalia of the species are not described in detail, but the measurements of the distal genitalia and their proportions are compiled in tables 1 and 2.