Carapace slightly broader than long, dorsal surface minutely granular; frontal region with acute to subacute submedians and an advanced median lobe. Orbits narrow, fissures prominent. Antero-lateral margins of carapace with five conspicuous, curved, acute teeth, first smallest. Chelipeds equal in size, dorsal face of propodus with two and outer face with three carinae. Pereiopods slightly compressed, segments dorsally carinate.
Carapace length up to 15 (15.5) mm.
Depth range from lower shore to about 183 metres on sand and gravel. Ovigerous from February-April with larvae in September.
Epi- and mesobranchial regions of carapace dark violet, sometimes with white patches, margins red; chelipeds and pereiopods banded with brown and yellow.
Firth of Forth, Yorkshire, Wash, Thames, East Channel, Wight, Portland, Channel Isles, Plymouth, Scilly Isles, Bristol Channel, Anglesey, Isle of Man, Dublin, Belfast, Clyde & Argyll, Minch, Mayo, Galway Bay, Fastnet, Cork.