Body strong, cylindrical.
Prostomium rounded anteriorly, dorsally separated from the peristomium by a weak groove. Nuchal slits relatively long, parallel, anteriorly bend outwards. Ocelli absent (but may be present in juveniles).
22-23 chaetigers. The first 6 chaetigers with glandular bands, anterior to the parapodia; in posterior segments glandular areas less clear. Anterior 3-4 neuropodia with a single strong spine, following neuropodia with a row of hooks.
The very small notopodia bear capillary chaetae.
Normally 2, rarely 1 or 3 posterior segments without chaetae (N. lumbricalis-detail).
Pygidium funnel-shaped, with 12-31 unequal and triangular cirri.
Up to 160 mm for 22-23 chaetigers.
Tube thick, straight or tortuous. Diameter outside 10 mm, inside 5.5 mm.
Anterior body half with red-brown spots or stains, especially dorsal and lateral.
The vertical distribution extends from the sublittoral down to 5000 m.
Arctic, North Pacific, North Atlantic to English Channel, North Sea, Skagerrak, Kattegat, the Big Belt and Öresund to Bay of Kiel.