Coxal plates very small, plate 2 little larger in male than in female. Head slightly prolonged forwards; eyes very large, rounded, protruding. Antenna 1 much longer than body, slender and weakly setose, flagellum equal to the length of the peduncle article 3, with five articles; accessory flagellum minute, 3-articulate. Antenna 2 about two-thirds of the length of antenna 1, slender, sparsely setose, flagellum shorter than the peduncle article 5. Gnathopod 1 small, simple, propodus shorter than the carpus. Male gnathopod 2 small, similar to gnathopod 1 except that the propodus is longer than the carpus, palm with 2 median spines. Female gnathopod 2 very large and robust, basis with a large anterodistal lobe, propodus elongate, palm with a large contorted proximal process and an acute distal tooth, dactylus setose with a small tubercle on the inner margin; in small specimens the proximal palmar process may be quite short and only weakly sinuous. Pereiopods 3 and 4 small, basis narrow. Pereiopods 5 to 7 elongate, carpus and propodus spinose; pereiopod 7 variable length, may be extremely long and slender. Peduncle and rami of uropods 1 and 2 with only a few marginal spines, outer ramus about three-quarters of the length of the inner one; rami of uropod 1 with a long apical spine. Telson rounded, shorter than the peduncle of uropod 2.
Up to about 8.5 mm.
Whitish mottled with red.
Depth range about 20 to 700 metres; usually found living on algae, hydroids, bryozoans or other organisms.
Arctic-boreal, widespread; north Atlantic, Pacific and Arctic Oceans; American and European Atlantic coasts, North Sea.