(Gmelin, 1791)
Description (shell):
Shell thin, fragile, obliquely oval along an anterior dorsal-posterior ventral axis. Inequilateral, anterior ears distinctly more prominent than posterior, sharply pointed; elliptical, dorsal gape on anterior margin and narrower gape along whole of posterior margin. Sculpture of numerous radiating ribs (approx. 50) and coarse concentric lines; ears, and parts of valves close to them, with concentric lines only. Margin serrated, growth stages clear. Hinge line straight, cardinal area broadly lozenge-shaped (L. hians).
Size:
Up to 25 mm long.
Colour:
Colour off-white, often stained dirty brown by surroundings.
Animal:
Thick fringe of orange or red pallial tentacles protrudes all around margin of shell. Like the tentacles of anemones, these have the power of taking hold. The animal is able to swim; when settled it uses its byssus threads to construct a nest of gravel and shell debris. The young ones often associate, several in one nest.
Habitat:
Lives on coarse bottoms, from lower shore to about 100 m.
Distribution:
Found in the northern North Sea only (Distr. L. hians). Extends south to the Mediterranean and the Canary Isles.