Shell. Differs only in details from that of C. gracilis. The apex is, in most shells, bulbous and wider than the initial postlarval whorls. There are up to 9 whorls, usually a little more tumid and with deeper sutures than those of gracilis. The apical angle may be a little larger than in that species. The ornament is fundamentally the same but the number of spiral ridges on each whorl of the spire is 1-2 less, and is markedly less on the last whorl.
The protoconch is smooth, has 1.5-3.5 whorls, and there is usually a sharp line separating it from the first postlarval whorl with its spiral ridging. Us diameter may be as much as 4.0 mm. The axis of coiling is very oblique to that of the adult shell.
Aperture. Like that of gracilis but relatively broader, and with a longer and narrower siphonal canal, which lies nearly in the long axis of the aperture. The outer lip arises about level with spiral ridge 12. The curvature of the columella near the origin of the canal is less marked than in gracilis and the triangular area on the last whorl devoid of periostracum is relatively smaller.
Colour. The shell is white, sometimes with brownish markings, under a yellow-buff periostracum.
Size. Up to 150 x 50 mm. Last whorl (including canal) = c. 70% of total shell height; aperture = 50% of shell height; canal = nearly 25% of shell height.
Animal, colour as in gracilis.
Geographical distribution. This is a northern, possibly circumpolar species. In the north-east Atlantic it extends south to the Norwegian coast and the north coast of Scotland; further south and in the Kattegat any shells found are subfossil. In America it extends to Labrador and Newfoundland.
Habitat. Soft bottoms from 10 to 3000 m.
Food. As for gracilis.