Description

 A dorso-ventrally flattened crustacean with an elongated rounded oblong shaped body. Males range in length from 7 to about 30 mm and females from 9 to 18 mm. Males brown in colour, occasionally with white markings. Females generally darker but with white bands along the sides of the body or alternating white and darker transverse bands. The distinct head bears two dorso-lateral eyes, a pair of short antennules, and a pair of antennae. Most of body is taken up by a thorax composed on seven sections (somites). The body ends in a short abdomen (two somites) and a distinct tail-piece (the pleotelson). The pleotelson in adults is characteristic, with slightly convex sides and a posterior end that is rounded in juveniles but bears two side processes in the adult giving a notched or emarginate appearance.