About Arion subfuscus (Draparnaud, 1805)
This species has an elongated, moderately thick body. The front of its mantle is slightly humped. It has a rather short neck, and its lower tentacles are also short. The upper tentacles are thick at the base, tapering toward a swollen, globular tip, and are blackish in colour. The upper portion of the head is also blackish and crossed by four longitudinal stripes. The mantle has a granular texture, and the back is covered with interconnecting net-like anastomosing ridges. The underside of the body is whitish, with a yellowish central area. The foot edge is grey and marked with small transverse black lines. Overlapping plate-like lamellae are visible at the tail. Overall body colour varies across individuals: the mantle and upper body are always a fairly dark brown, with a black band along each side of both the mantle and body. Variety α of this species has a reddish tint that is most prominent toward the middle of the mantle, and especially on each side of the body below the two black bands. Variety β has an ashen or greyish base tint, against which the blackish net-like network of anastomosing ridges stands out clearly on each side of the body. This species is native to Eurasia, and has been introduced to eastern North America.
