Deroceras (Deroceras) parium Wiktor & Mylonas, 1981
External: Slug dirty or brownish cream with numerous darker blurry spots, or evenly brown or blackish with diffuse and merged spots; lowest parts of sides lighter; posterior part of body behind mantle becoming thinner, last section with a distinct keel; sole creamy, in darkest slugs the lateral zones of the sole are dark.
Internal: Penis and penial gland look like one single elongated organ; penial gland with some papillae on the edges; vas deferens opens at base of penial gland; retractor muscle unforked; stimulator very large, filling almost the entire part of the spherical part of the penis, and completely flat; rectal caecum has the shape of a vestigial enlargement.
Up to 20 x 4 mm (preserved).
Greece: islands of Páros, Andíparos, Náxos, Amorgós.
Type locality: Greece: Páros island, Agii Pándes.
Nothing published on habitat and ecology.