Carapace suboval, much broader than long, dorsal surface moderately convex and with numerous long, transverse, setose carinae; a pair of very broad concave submedian lobes and an advanced, broad, subacute to rounded median lobe; outer ventral margin of orbit with moderately narrow incision. Antero-lateral margins of carapace with prominent equally-developed teeth. Chelipeds equal in size and with carinae; pereiopods stout and setose, carpus-dactylus of second to fourth with longitudinal carinae, propodus with one setose longitudinal ventral carina extending length of margin and, on fourth pereiopod, a secondary short carina sometimes present distally; dactylus of second to fourth pereiopods styliform, of fifth broadly lanceolate with pronounced median carina.
Carapace length up to 23 (43) mm.
Depth range up to 100 metres, on coarse sand and gravel. Ovigerous April-August.
Carapace and pereiopods reddish brown; carapace sometimes with patches of yellow or red.
?Yorkshire, Wight, Portland, Channel Isles, Plymouth, Scilly Isles, Isle of Man, Dublin, Belfast, Clyde & Argyll, Minch, Mayo, Galway Bay, Fastnet.