Malacolimax tenellus (Müller, 1774)
Defends itself from predators by producing much mucus when perturbed (Kerney & Cameron 1979) or by autotomizing (self-amputating) its tail, followed by fleeing and hiding (Solem 1974; Pakarinen 1994).
External: Stout body; bright yellow, sometimes a bit orange or green, with faint darker stripes on sides; small tubercles on skin, which is translucent; dark head and tentacles; short, weak keel; yellow-white sole and edge of pneumostome; thin, transparent yellow to orange body mucus and clear foot mucus (Quick 1960; Kerney & Cameron 1979; Wiktor 1996).
Internal: Internal shell 3.5 x 2 mm; dark ovostestis; short, thick penis with bulges; "crescent-shaped", often dark swelling where vas deferens meets the penis; penis shorter than 1/2 mantle length; 4 weak apical folds and 3 strong lateral folds in penis; long, ovate spermatheca with a thin duct of similar length, connected to base of penis; thick, cylindrical oviduct (Quick 1960; Kerney & Cameron 1979; Wiktor 1996).
Eggs: 3.6 x 3.1 to 3.3 x 3.0; light amber, translucent, and sticky; ~15 per clutch (Quick 1960).
Juveniles, at hatching: 6 mm long; slight keel at tail end; white translucent body; purplish tentacles (Quick 1960).
Up to 50 mm long extended. When preserved, up to 35 mm long, 8 mm wide, mantle 18 mm long (Wiktor 1996).
Central and N Europe. W to Pyrenees Mts, E to Kazan (Russia), N to central Scandanavia, S to the Alps (Wiktor 1996).
Usually occupies old, moist deciduous forests, especially beech (Wiktor 1996; Kappes 2008). Unusual in being one of few slug species that inhabits coniferous forest (Quick 1960). Also sometimes found in parks and cemeteries. Takes shelter under leaf litter and fallen logs (Wiktor 1996).
Lives about one year. Spends winter as an egg (Wiktor 1996).
Feeds on mushrooms (Wiktor 1996).