Carapace appreciably narrowed anteriorly, frontal region produced as a tapering bifid rostrum not extending beyond proximal half of fifth peduncular segment of antenna; carapace surface with numerous hook-setae prominent on rostrum, regions swollen and with tubercles; second and third peduncular segments of antenna slender and without spines or spinules in post-pubertal crabs; eye-stalks totally visible from dorsal aspect. Second to fifth pereiopods very slender, merus of second shorter than length of carapace and rostrum, dactylus of fourth and fifth pairs short and moderately curved, spines on inner margin of dactylus of fifth not extending beyond distal third of margin. Female chelipeds slender.
Male chelipeds stout and spinous, merus long and with a distal median spine, propodus swollen, a moderate 'gape' between inner margin of propodal prolongation and dactylus.
Carapace length up to 16 (28) mm.
Depth range from lower shore to about 130 metres, chiefly on muddy sand. Ovigerous throughout year, larvae May-January.
Carapace and pereiopods greyish to yellowish or reddish-brown, sometimes with white markings.
Shetland, Orkney, Moray Firth, Aberdeen, Firth of Forth, Northumberland, Dogger, Yorkshire, Wash, Thames, East Channel, Wight, Portland, Channel Isles, Plymouth, Scilly Isles, Bristol Channel, Anglesey, Liverpool Bay, Isle of Man, Dublin, Belfast, Clyde & Argyll, Minch, Donegal Bay, Galway Bay, Fastnet, Cork.