Mexico: Guaymas, 20 fathoms (Lowe). Type 155635 ANSP.; paratypes in Lowe collection.
The shell is small, moderately solid, inequilateral, white, glossy. Anterior end broadly rounded. Posterior end rapidly tapering to a point, the dorsal margin straight at first, becoming concave towards the point. Ventral margin convex in the anterior half, very weakly so in the posterior half. Lunule narrowly lanceolate, weakly corrugated transversely. Posterior dorsal area flattened, rising a little to the valve edges, longitudinally closely costulate. Sculpture elsewhere of fine, regular ridges as wide as their intervals, obsolete in a radial concavity in front of the posterior ridge. There is a weak radial angulation near the anterior end. followed by a slight flattening. Teeth rather strong and high, 12-10, with two or three minute additional denticles on each side of the rather small resilium.
Length 6 mm., height 3.4 mm., diam. 2.3 mm.
Peculiar in the smooth band preceding the posterior ridge. The hinge is strong for so small a species.