Shell elongate, narrow; umbos central, low; posterior dorsal margin slightly concave, anterior dorsal margin arched almost level with umbo, anterior margin regularly rounded, ventral margin gently curved with shallow sinuation to form a broad, moderately elongate, rostrum; shell ornamented with up to six ill defined concentric ridges, best formed anteriorly, becoming progressively fainter posteriorly where five irregular growth lines are well marked; oblique, ill defined rostral ridge; two or three faint rostral striae; hinge without teeth. The septum is thin and has eight paired pores arranged in a V-formation with the apex posterior to the foot. There are few posterior dorsal muscle attachments onto the shell, but there is a horizontal connection with the intersiphonal septum. The posterior septal muscles are weak. The lateral septal muscles are continuous. The anterior septal attachment to the shell is double, with well developed inner longitudinal muscles that cross posterior to the foot. The anterior and posterior mid-septal muscles run together and are more straight than those of C. obesa. The pores do not have the dorsally directed inner flanged lips but form a straight hole through the tissue with two distinct bands of peripheral cilia. The posterior palps are well developed and cup-shaped. The anterior palps are more or less triangular. The tentacles are club-ended. The siphons and other features of the anatomy are as for Cuspidaria obesa. Maximum shell length is 5.3 mm.