Carapace slightly longer than broad with flat, grading to bead-like tubercles; margin of frontal region concave, often with faint median suture; inner epibranchial and mesobranchial regions with low bosses, often capped with tubercles. Antero-lateral margins of carapace sinuous and moderately cristate merging with postero-lateral margins to form continuous curve. Third maxilliped narrowing anteriorly. Chelipeds equal in size, stout and moderately tuberculate, margin of merus tuberculate; pereiopods granular, sometimes with small, rarely spiniform, tubercles. Female chelipeds shorter than in male; abdominal segments 4-6 fused. Male chelipeds with propodus inflated, posterior margin of carapace often strongly bifid; abdominal segments 3-5 fused; distal portion of first pleopod thin, apex truncate ; inner margin of second pleopod strongly expanded.
Carapace length up to 8 (11) mm.
Depth range from 7 to 82 metres, muddy sand and gravel. Ovigerous in spring, larvae July-November.
Variable, carapace reddish-yellow to reddish-white with red spots, pereiopods yellowish.
Moray Firth, Aberdeen, Firth of Forth, Northumberland, Yorkshire, Thames, Channel Isles, Plymouth, Scilly Isles, Bristol Channel, Anglesey, Liverpool Bay, Isle of Man, Dublin, Belfast, Clyde & Argyll, Minch, Galway Bay, Fastnet, Cork.