Arion (Arion) vulgaris Moquin-Tandon, 1855
External: Variable in color, but usually brown-green, with some gray or brown (may also be dark gray, orange, brown, to green-gray); stripes on sides of juveniles and often on adults, with lyre pattern on mantle; head and tentacles dark; foot fringe may be darker or lighter than body; coarse tubercles; white sole; clear mucus (Quick 1960; Kerney & Cameron 1979).
Internal: Very dark ovotestis; ring at end of epiphallus, and pigmentation towards its base; wide, pigmented middle part of free oviduct, with two internal folds; bulge at base of spermatheca duct; thick, glandular walls of lower atrium, which is sometimes yellow with tiny white granules; spermatophore 20 mm long, with spiral serration (Quick 1960).
Similar to A. ater, but pneumostome does not expand as much as that of A. ater, and distinguishable with dissection; similar to A. subfuscus but larger tubercles and longer spermatheca duct, and side stripes are closer together than on A. subfuscus (Quick 1960; Kerney & Cameron 1979).
Eggs: 3 x 3.25 mm; turn yellow with age; to 50 eggs per clutch, aggregated by mucus (Quick 1960).
Juveniles: Dark stripe on each side (Quick 1960).
Activity in the field is dependent on both temperature and vapor pressure deficit (Crawford-Sidebotham 1972).
To 70-100 mm long extended (Kerney & Cameron 1979); preserved or contracted: to 80 mm long (Sysoev & Schileyko 2009). .
Native to: SW Europe; Portugal, Spain, Andorra, France, Algeria, Italy, Liechtenstein, Switzerland, UK (Wiktor 1983).
Nonnative to: W Germany, Bulgaria (Wiktor 1983); Kaluga (W Russia) (Sysoev & Schileyko 2009).
Synanthropic habitats, including cultivated lands and wastelands; natural habitats on coastlines (Kerney & Cameron 1979); also forests and forest edges (Wiktor 1983).
Feeds on soil fungus (Maraun et al. 2003); plants (lettuce, carrot, etc.) in the lab (Quick 1960).