Usual maximum length is 400 mm and weight 1.2 kg (Roper et al.,1984), but it occasionally grows larger. This one was 1.41 Kg and 660 mm when fully extended. Ventral surface white, hence Spanish and French vernacular names “blanco”, “blanche”. Caught in a lobster creel with exoskeleton of a consumed lobster, Scapa Flow, Orkney. April 1974.