 On the head and neck are a few regular rows of rugae, somewhat quadrate in outline; on other parts of the body the rugae appear to be oval-shaped, irregular in size, and not forming continuous rows.The mantle has a sharp even margin, and a deeply incised line or groove rather less than 2 mm from the edge.On the underside of the mantle is the usual prominent lappet which conceals the respiratory and anal pores, and in addition to this is a long narrow fold on the left side.