Carapace suboval and broader than long, dorsal surface relatively flat and smooth to minutely granular, frontal region slightly produced, median and sub-median lobes equally developed and subacute, median advanced; outer ventral margin of orbit with a moderately narrow incision. Antero-lateral margins of carapace with flat spinose teeth, fourth longer than third and with margin almost straight. Chelipeds equal in size and stout, outer margin of carpus with two lobes, carpal process acute and broad, propodus with conspicuous longitudinal carinae; second to fourth pereiopods moderately thin, ventral margin of propodus with one longitudinal carina extending length of margin (setose on second pereiopod), dactylus styliform, of fifth pereiopod broadly lanceolate, width more than half length, sometimes with a faint median carina; merus of fifth pereiopod not extending beyond proximal half of merus of fourth.
Carapace length up to 17.5 (37) mm.
Depth range from rock pools to about 73 metres, on sand and gravel. Ovigerous April-July, larvae spring and summer.
Carapace and limbs greenish brown, cervical groove often with row of white spots.
Shetland, Orkney, Firth of Forth, Northumberland, Yorkshire, Dogger, Wash, Thames, East Channel, Wight, Portland, Channel Isles, Plymouth, Scilly Isles, Bristol Channel, Anglesey, Liverpool Bay, Isle of Man, Dublin, Belfast, Clyde & Argyll, North Donegal, Mayo, Galway Bay, Fastnet, Cork.