Carapace subcircular, smooth, slightly broader than long. Antero-lateral margins of carapace with five acute, broad teeth; frontal region with subacute median and submedian lobes. Merus of third maxillipeds longer than broad, with a small distal notch on inner margin near articulation with carpus. Chelipeds equal in size, propodus and dactylus compressed. Second to fourth pereiopods compressed, dactylus broad and lanceolate. Propodus and dactylus of fifth pereiopods broad and strongly compressed, dactylus suboval.
Carapace length up to 44 mm.
Depth range from offshore surface waters to 500 metres. A fish predator; enormous numbers washed ashore after storms. Ovigerous May-December.
Carapace reddish brown, sometimes with white markings near cervical groove; dactylus and propodus of chelipeds distally yellowish.
Shetland, East Channel, Wight, Portland, Channel Isles, Plymouth, Scilly Isles, North Cornwall, Bristol Channel, Liverpool Bay, Fastnet, Cork.