Body long, thorax cylindrical and firm, abdomen very long, tapering and soft. Tentacles numerous, long. Upper lip narrow, about enclosing the mouth. Buccal segment laterally and ventrally forming large, protruding lobes. Many eyespots (L. conchilega-detail).
Three pairs of gills on segments 2-4. Gills about equally large, arborescent, with short, thick stems and richly branched crowns.
Very distinct, long lateral lobes on segment 3, laterally covering segment 2. 14-20 ventral shields.
Seventeen thoracic chaetigerous segments.
Notopodial chaetae from segment 4. Uncinigerous tori from segment 5, very long on the thorax. Uncini in double rows on segments 11-20. Pygidium with 4 small papillae. Notopodial chaetae smooth with narrow brims. Uncini with one big and several smaller teeth.
Up to 300 mm for 300 segments.
A thin, cylindrical layer of secretion encrusted with sand and shell fragments (L. conchilega-drawing). Anteriorly expanded like a flattened funnel and provided with one or more crowns of often branched (Lanice tube), long sand-encrusted fringes (L. conchilega-tube).
In life yellowish, pink or brown, tentacles pale, gills red, ventral shields partly reddish. Ripe females reddish brown, ripe males yellowish white. In alcohol yellowish grey or pale yellow.
mainly on more or less mixed sand bottoms, rarely on muddy bottoms, also among Zostera and benthic algae, and on shifting substrata; upper eulittoral to depths exceeding 1700 m; euhaline to polyhaline.
Eastern North Atlantic, Mediterranean, Persian Gulf, Pacific, Australia.
East Greenland, Iceland, the Faeroes, Shetland, Orkneys, northern Norway (empty tubes only), Trondelag, western Norway, Skagerrak, Kattegat, the Oresund and the Belts, Danish west coast, the Netherlands, southern North Sea, east coast of Great Britain.