Body anteriorly slightly flattened, posteriorly pointed.
Prostomium broadly rounded, with two small eyes at the posterior margin.
Thorax with 11-17 chaetigers. Thoracic notopodia with a single postchaetal lobe, a bundle of capillary chaetae and a few forked chaetae. Thoracic neuropodia with a postchaetal lobe with a single triangular projection.
Abdominal notopodia as thoracic notopodia. Abdominal neuropodia bilobed, with few chaetae and few protruding aciculae.
Gills start at chaetiger 4-6 (N. quadricuspida-detail).
Pygidium with four lobes and four short cirri.
Up to 80 mm for 130 segments.
Yellowish, pale pink or flesh-coloured, with red gills.
Generally in low water between seaweeds and rocks. Also on soft bottoms between shells and stones.
Arctic, North Pacific, North Atlantic to the northern North Sea and Skagerrak.