Shell. Very similar to that of C. tubercularis from which it differs only in details: it is thinner and more transparent; the spire is perhaps more slender and relatively longer though it has fewer whorls (12 in all); the sutures are deeper; the base below the prominent spiral keel of the last whorl is smooth.
The protoconch has 4-4.5 tumid whorls of which the first 1-2 bear numerous small tubercles as in tubercularis; the others have some tubercles persisting near the sutures but the basal half or so of the whorl has numerous raised lines, slightly prosocline in their orientation. It measures about 600 x 400 µm
Aperture. Like that of tubercularis.
Colour. Pale yellow-brown.
Size. 7x2 mm. Last whorl = 35-40% of total height; aperture = 20-55% of total height. Animal. As in tubercularis. Colour. Paler than tubercularis.
Geographical distribution. A southern species spread from S. W. England to the Mediterranean.
Habitat. Like tubercularis this species associates with sponges, especially Suberites domunculus. It is not uncommon.