L. conchilega has an elongated body, consisting of two regions. The swollen front region has hair-like as well as hooked chaetae; the long, slender tail region only hooked ones. The species can reach a length of up to 150 mm with up to 300 segments. The head bears a dense tuft of long, thin tentacles. The first segment projects forwards, forming two lobes at both sides of the head. The next three segments carry branched gills. The worm is yellowish, pink or brown coloured with blood-red gills and white tentacles. L. conchilega builds a characteristic tube, consisting of cemented sand grains and shell fragments and with a typical fringe at the top end (Hartmann-Schröder, 1971; Holthe, 1986; Fish & Fish, 1989; Hayward & Ryland, 1990).