Deroceras (Deroceras) kasium Rähle, 1993
Obviously an endemic species of Kasos island.
External: Slug unusually small; ochre to pale grey; back and sides covered with dark brown spots in skin grooves, forming a reticulate pattern; mantle darker than the rest of the body, except a lighter plate around pneumostome; mantle evenly pigmented, with darker spotting at the edges, 40 % of body length; sole pale.
Internal: Very typical penis and appendix: penis very small, and non-constricted, appendix larger, hook-like bent, with two unilateral constrictions at the surface of the bulging part, subdividing the appendix into three sections; retractor insertion marking probably the border between penis and appendix; penial gland set apically on penis with 5-6 equally long and partly bifurcate processes; practically no rectal caecum.
Differs from other nearby Deroceras because of small size (Wiktor 2000). .
Up to perhaps 18 mm (preserved up to 13 mm; adults can have smaller sizes, usually 9 mm).
Greece: Kasos island.
Type Locality: Greece: Kásos, gorge near Arvanitochori.
In Mediterranean shrubland vegetation, finds shelter under stones.