(Linné, 1758)
Description (shell):
Shell cap-shaped, a rapidly expanding planospiral of up to three whorls; covered by periostracum. Sculpture of numerous spiral striae and fine growth lines; periostracum projects as frilled edge beyond aperture, successive positions of aperture marked by series of similar fringes on last whorl. Aperture large, oval, with finely serrated margin (C. ungaricus-drawing).
Size:
Up to 40 x 25 mm across the aperture and 15 mm high.
Colour:
White, with horn coloured periostracum.
Animal:
Snout short, with long, dorsally grooved, non-retractable pseudoproboscis; mantle thick, double-edged. Foot oval, without operculum.
Habitat:
Sublittoral (occasionally at LWST), on stones and shells (especially those of living scallops and Turritella communis ) down to 850 m.
Distribution:
Widely distributed from West Africa to northern Norway; less common in North Sea (Distr. C. ungaricus).