Jumping-slugs are a small group of slugs endemic to western North America. They are relatively large (ca. 60 mm long) slugs with a distinctive appearance (a pronounced hump). The tail is laterally compressed, keeled, and tipped with a horn-like protuberance (caudal horn). The sole of the foot is often bright yellow or orange. This species is found from sea level up to 1060 m in older coniferous forests.
A medium-sized slug; grey with cream mottling; dorsal hump/mantle nealry black to yellowish, densely with blue-black and grey; end of tail with a fleshy ?horn?.