Nucula sulcata

Bronn, 1831

Shell solid, equivalve; inequilateral, beaks behind the midline; triangular in outline. Fine radiating striations and coarser concentric lines give a decussate effect, well-marked at hinge line. Anterior hinge line curving about the horizontal when the posterior is vertical; 20-30 hinge teeth anteriorly, 10-14 posteriorly; lunule crossed by strong transverse corrugations, escutcheon distinct, with depressed border and pouting hinge line. Margin of shell crenulate (N. sulcata-drawing).

Up to 20 mm.

Shell white or grey; periostracum matt, light yellow to brown, often with darker patches, and brown or black incrustations about hinge line.

On mud and sand, from 10-200 m. Mostly off west coasts.

Found in the northern North Sea (Distr. N. sulcata). Distributed from northern Norway to the Mediterranean and West Africa.