Body short, thick, with a very short, conical abdomen. Prostomium with three lobes and a pair of glandular ridges on the middle lobe, no eyespots. Two groups of comparatively large gills widely separated at middorsum and connected by membrane, three gills of each group arranged in an inverted triangle, the fourth one nearer to the middorsum and obliquely behind the posterior one of the three.
Fourteen thoracic segments with notopodia with capillary chaetae, the posterior eleven also with neuropodia with uncini. Eight uncinigerous abdominal segments. Uncini with a row 4-5 teeth, the inferior of which are double.
Pygidium with a pair of small papillae.
Up to 12 mm.
Conical, irregularly bent, comprised of a thin layer of secretion and a thick layer of mud and some shell fragments, possibly also some mussle byssus. Up to 3 mm wide.
In alcohol orange yellow or pale yellow.
Mainly on muddy or mixed bottoms; upper sublittoral to depths exceeding 1000 m.
Eastern North Atlantic, Mediterranean, Canadian Arctic, Quebec, Atlantic coast of the USA, Arctic, Japan, East India. East Greenland, Iceland, Svalbard, Norwegian Sea, entire Norwegian coast, north coast of Jutland, Skagerrak, Kattegat, southeastern North Sea.