Carapace heart-shaped, dorsal surface smooth, frontal region slightly projecting, median and submedian lobes subacute, orbits wide. Antero-lateral margins of carapace with five teeth, fourth often very small. Chelipeds slightly unequal and somewhat compressed, dorsal margin of carpus-dactylus cristate and setose; second to fifth pereiopods compressed, cristate and setose, dactylus lanceolate; dactylus of fifth pereiopod broadly lanceolate.
Carapace length up to 19 (27) mm.
Depth range; reported from between tide marks and beyond, and 100-150 mm below surface of sand, probably swims just above sand surface. Ovigerous June, larvae summer and autumn.
Carapace reddish brown, variegated with dark brown; also 'fleur-de-lis' in centre of carapace.
Moray Firth, Aberdeen, Firth of Forth, Yorkshire, Wash, Thames, East Channel, Wight, Portland, Channel Isles, Plymouth, Bristol Channel, Liverpool Bay, Dublin, Belfast, Clyde & Argyll, Donegal Bay, Galway Bay.