(Oersted, 1843)
 
Description: 
Body short, with triannulate segments. Epidermis reticulate with a regtangular pattern. Ventral side without an obvious furrow.
Prostomium small and bilobed, with 2 long, dorsolatteral nuchal slits. Eyes absent.
Noto- and neuropodia simple mounds, each with a bundle of capillary and forked chaetae. Dorsal and ventral cirri absent. 
Four to six pairs of arborescent gills, starting at notopodium 2. 
Pygidium short, cylindrical. 
Size: 
Up to 40 mm for 40 segments, when contracted; twice as long when extended. 
Colour:
In alcohol yellow to colourless. 
Habitat:
On mud and mixed bottoms, from the upper sublittoral to over 2000 m. It lives in U-shaped burrows which are supported by slimy secretions.
Distribution:
Arctic, North Atlantic to Mediterranean, North Sea to Ă–resund, South Africa.