Shell large, elongate-conic, covered with a grayish olivaceous periostracum. Nuclear whorls decollated. The postnuclear whorls have a weak median spiral cord. Anterior to this they curve convexly to the slightly shouldered summit. This area is marked by retractively curved incremental lines only. The anterior half of the last whorl and base are inflated, strongly rounded, and marked by strong incremental lines which vary in strength and almost give to the base an obscurely ribbed aspect. Columella rather stout, moderately long, twisted. The left outline of the base and columella is moderately concave. Aperture elongate pearshaped with the anterior canal moderately long and rather broad. The posterior sinus is broad and extends from the summit to the median cord. Anterior to this the outer lip is protracted. The inner lip is obliquely truncated, free for about two-fifths of its basal length. The posterior portion appears on the columella as a smooth resorption area which also extends over the parietal wall.
The type, U. S. N. M. No. 212323, was dredged by the U. S. Bureau of Fisheries steamer Albatross at station 3187 off Point Sur, California, in 298 fms., on yellow sand and mud bottom; bottom temperature, 41.1° F. It has 5 whorls remaining and measures: Height, 16 mm.; greater diameter, 7 mm.; length of aperture, 8.9 mm.

It is easily distinguished from C. adrastia Dall by having a much longer aperture and the spiral keel much less developed.