A. Milne Edwards, 1867
Carapace with dorsal surface flat and smooth, sometimes sparsely punctate, frontal region slightly produced, sub-median lobes very broad. Antero-lateral margins of carapace with five obtuse to subacute teeth sometimes with margins tuberculate, fourth prominent, at least fourth and fifth setose ventrally. Chelipeds slightly unequal, stout and sparsely punctate, often with short transverse grooves bordered by flat tubercles that are sometimes scale-like; second to fifth pereiopods stout and somewhat compressed, margins of merus-propodus densely setose, setae on fourth and fifth pereiopods long. Male inner proximal margin of first pleopod expanded and with a small lobe.
Carapace length up to 15 (21) mm.
Depth range from lower shore to 110 metres. Ovigerous March-April, larvae August-October.
Carapace yellowish with red patches, chelipeds and pereiopods yellowish, distal propodus and dactylus of chelipeds brown.
Shetland, Thames, Channel Isles, Plymouth, Scilly Isles, Bristol Channel, Anglesey, Isle of Man, Dublin, Belfast, Clyde & Argyll, Minch, Mayo, Galway Bay, Fastnet, Cork, Nymphe Bank.