(O.F. Müller, 1776)
Body long and cylindrical, tapering gradually to the posterior end.
10-12 pairs of radioli, connected at the base by a membrane.
Operculum is a membranous cup or funnel with a rather flat lens-shaped plate with concentric lines.
Peristomium without eyes, the next segment without collar chaetae.
Thorax with 6 chaetigers. Thoracic notopodial chaetae are capillaries and slightly bent, winged chaetae. Neuropodia bear uncini with 16-22 teeth in a single row.
Abdominal uncini are like those on thorax. Capillary chaetae are present on the most posterior 30-25 segments. They are long, thin capillary chaetae.
Between thorax and abdomen two segments without chaetae.
Pygidium with 2 round, small papillae.
Up to 20 mm long for 60 segments.
Characteristic in being tusk-shaped, not adhered to substratum, made of two layers, the outer thick and vitreous, the inner thin and opaque.
Abdomen reddish, crown with reddish cross bands.
Lives unattached to substrata (sand or mud); sublittoral.
Probably world-wide, English Channel, northern North Sea, Skagerrak, Kattegat and northern Öresund.