Calyptraea chinensis

(Linné, 1758)

Description (shell):
Shell patelliform, rather depressed, with concave anterior profile; apex with small nipple-shaped beak, often slightly coiled. Sculpture limited to slight, sometimes stepped growth lines, sometimes with small tubercles. Aperture almost circular, with thin, bevelled edge, often reflecting contours of surface to which animal was attached. With a posterior tongue-shaped internal partition (C. chinensis-drawing).

Up to 15 x 5 mm.

White or yellowish, with pearly white interior.

Snout short; head elongated behind tentacles, with large propodial folds (cephalic lappets). Mantle edge thickened, with repugnatorial glands; mantle cavity and ctenidium large. Foot large, without operculum.

Sublittoral, on stones and shell gravel associated with soft substrata, to 20 m.

Distributed from north-west Africa and Mediterranean to west coast of Scotland (Loch Ryan); only in the southern North Sea (Distr. C. chinensis).