Body quite slender; urosome segment 1 in male with a setose lobe on the dorsal margin; pereion segments 5 to 7 and pleon segments 1 to 3 each with a small group of long, fine setae on the dorsal margin; number of setae variable. Epimeral plate 3 posterodistal angle with a minute tooth. Corneal lenses absent, only two small patches of reddish pigment in fresh material. Antenna 1 slightly more than half the body length, peduncle article 2 much longer and more slender than article 1, flagellum about 25-articulate, in female only with long setae; female antenna 2 equal in length to antenna 1, flagellum setose; male antenna 2 much longer than antenna 1, flagellum filiform. Gnathopods 1 and 2 slender and setose, weakly subchelate, propodus oval and much shorter than the carpus. Pereiopods 3 and 4 merus elongate and fringed with plumose setae, dactylus little longer than the propodus. Pereiopods 5 and 6 carpus robust with few marginal spines and a very long distal spine, propodus long and slender, dactylus large and strongly curved. Basis of pereiopod 7 broad, posterior margin about straight, distal margin broadly rounded; ischium, merus and carpus flattened and weakly spinose, propodus slender and only little shorter than the carpus, dactylus very small. Uropod 3 with plumose setae, inner ramus with 2 to 4 spines on the inner margin. Telson narrowly rounded, cleft to the mid-point, with several long setules.
Up to 15 mm, occasionally over 20 mm.
Deep water, from 70 to 3000 metres.
Arctic Ocean, North Atlantic, American and European coasts, widespread and frequently recorded; southern limit around the Scottish coasts and the Skagerrak.