Clausinella fasciata

(da Costa, 1778)

Description (shell):
Shell subtriangular, rather flat, umbones prominent. Sculpture of up to 15 broad, bold, concentric ribs, round in section with fine concentric striations between. Each growth stage indicated by two closely conjoined ribs. Anterior margin distinctly concave in front of umbones. Lunule shallow but distinct, usually deeply pigmented. Escutcheon elongate, narrow; clear on left valve but partly obscured on right. Three cardinal teeth in each valve. Adductor scars and pallial line distinct, pallial sinus small, U-shaped. Margin very finely crenulate (C. fasciata-drawing).

Up to 25 mm long.

Colour very variable, from white through shades of yellow and brown to pink and deep purple; typically with bands, rays, or streaks of colour on a paler ground. Periostracum thin, indistinct. Inner surfaces white.

Mantle bordered with red and fringed with white. The short yellow siphons are united, save at the tips, where they are fringed with white. The thick, white foot is lance-shaped.

In coarse gravels, usually with sand or shell; offshore to about 100 m.

From Norway to the Mediterranean and the Canary Isles (Distr. C. fasciata).