Shell small, fusiform. Apex worn, but shaped about as in B. perfectus. Outlines of spire slightly concave above, convex below. Color between cinnamon and cinnamon-brown with a while band at the periphery and a short distance above the suture on the spire, above it a spiral series of brown spots on the right slopes of the ribs. Whorls 9, the last two very slightly concave below the suture, which is linear, not impressed. Sculpture of small, somewhat sinuous axial ribs, strongest in the peripheral region, running to the suture, or on the last whorl almost to it, and continuing over the base to the anterior canal; on the last whorl about 19 ribs. Upon the canal there are a few excessively weak cords, but elsewhere no spiral sculpture. The aperture is brown within. Siphonal sinus shallow. The outer lip is broken, but there was a rounded anal sinus separated from the suture by a very heavy callous pad at the posterior end of the parietal wall. The columella is moderately calloused, the outer edge of the columellar lip a little raised.
Length 6 mm., diam. 2.3 mm.

This species appears related to I. perfecta, besides the obvious differences in costation and color, it does not have a distinct varix on the back of the last whorl, behind the lip, though there is a moderate swelling immediately behind it, and the columellar lip is not closely appressed as in that species.

San Juan del Sur, Nicaragua