Urosome segments 1 to 3 with only few dorsal spines. Epimeral plate 3 with the posterodistal angle obtusely quadrate, posterior margin about straight and with few small setules. Head with lateral lobes broad; eyes large, elongate, weakly kidney-shaped. Antenna 1 and 2 short and sparsely setose; antenna 1 slightly longer than 2, peduncle article 1 stout and only little longer than 2, flagellum about 17-articulate; accessory flagellum about 4-articulate. Antenna 2 flagellum little shorter than peduncle and about 13-articulate; calceoli absent. Gnathopods robust. Male gnathopod 1 propodus broad, palm oblique and weakly convex, with close set group of angle spines. Male gnathopod 2 propodus slightly more elongate than 1, palm similar. Female gnathopod 1 propodus rectangular, palm convex and weakly oblique, spines grouped close to palmar angle. Female gnathopod 2 propodus more elongate than 1 with palm almost transverse. Pereiopods 3 and 4 sparsely setose. Pereiopods 5 to 7 rather sparsely spinose; pereiopod 5 basis with posterodistal angle freely produced, distal angle of pereiopods 6 and 7 weakly produced; propodus distinctly longer than carpus. Uropod 3 outer ramus broad and elongate, margins strongly spinose but without setae, inner ramus very small. Telson lobes each with 1 or 2 lateral spines and 3 apical spines, and with pair of small dorsolateral plumose setae.
Length of male about 4-7 mm, female rather larger about 5-8 mm.
Pale slate-blue to greenish blue.
Intertidal, ranging over the shore from high to low water neaps in areas of fresh water seepage or outflow; usually found on coarse gravel beaches, but not in the presence of muddy deposits.
Around British Isles, Norway, Iceland, Netherlands and Brittany.