Deroceras (Deroceras) ilium (Simroth, 1901)
External: Gray-pink body in life, gray-yellow to ochre when preserved; large dark red-brown spots on mantle and dorsum, excluding keel; sides light; head gray; sole light (Wiktor 2000).
Internal: Penis rounded with a bulging basal part; narrower upper part of penis, separated from basal part by a constriction; short, twisted appendix on penis; penial gland "fleshy, thin-walled, and lanceolately narrowed structure" with a corrugated edge; vas deferens attached to side of basal penis section; short retractor muscle with three branches attached to penis (middle and base of appendix and middle of penis); thin, cone-shaped stimulator inside penis usually protruding into penial gland; shallow caecum on rectum (Wiktor 2000).
Like D. osseticum, but head and neck are gray rather than white and much smaller penial appendix (Wiktor 2000). .
To 40 mm long (Wiktor 2000). .
Upper reaches of Terek, Podkumok, Kodori Rivers, and E tributaries of Kuban River (Likharev & Schileyko, MS; in Sysoev & Schileyko 2009); central and NW of north Caucasus, Abkhazia (Wiktor 2000).
Type Locality: Il Mountain, Sapickaya buka, near Odzhonikidze, Osetia, the Caucasus (Wiktor 2000). .
Montane deciduous and mixed forests; sometimes by streams; in leaf litter and shady habitat (Wiktor 2000). .