Shell short-conical, covered perforate, bluish-black, spirally lirate. Sculpture consisting of close spiral lirae, 8 to 11 on the penultimate, 17 to 20 on the body whorl, crossed by fine growth-lines. Colour bluish or purplish black, the apex mostly worn white. The inner lip is more expanded than in the species, completely covering the perforation. All the other characters are the same as in C. tenebrosus.
Diameter, 7-10,5 mm. ; height, 10,5-14,5 mm.
Hab.—The same as C. tenebrosus, but more abundant.