Among terrestrial slugs in BC, this is an unmistakable species, recognized by its pale colour and long, worm-like form.
Slug-like, medium-sized (length, 30–60 mm; width, 3–5 mm wide). Animal very slender, worm-like when active. Pale translucent grey, bluish-grey or yellowish-grey, with the keel, back and head darker bluish-grey in adults; juveniles are nearly white. Mantle ca 1/3 the length of the body, pointed behind, and with a pattern of fine concentric wrinkles and a groove that approximately parallels the mantle’s right edge. Pneumostome near the midpoint of the mantle. Keel prominent and extending from tip of tail to mantle.
Genitalia figured by Gittenberger et al. (1984).
Internal, plate-like, edges irregular.