O.F. Müller, 1776
Body long and slender.
Prostomium short, subconical, with two ovoid frontal palps and two large globular ventral palps. Antennae with a few faint basal rings; the three posterodorsal antennae long. Young specimens with two small eyes. Peristomium without cirri and either as long as or shorter than first chaetiger.
Parapodia of first three chaetigers enlarged, especially those of chaetiger 1, and turned forward and downward. Dorsal cirri short, varying from awl-shaped to cylindrical. Ventral cirri on first four chaetigers short, awl-shaped to conical; from chaetiger 5 onwards forming cushion-like lobes (H. tubicola-parapodium).
Chaetae of first chaetiger unidentate curved hooks; chaetae of second chaetiger similar but bidentate or with frayed tips. Chaetae of following parapodia before the gills of two kinds: 1) winged capillary chaetae; 2) delicate comb-chaetae. In addition to the above two types of chaetae, parapodia of gill region have two stout bidentate hooks. Chaetae and aciculae light amber coloured (H. tubicola-chaetae).
Gills start between chaetigers 18 and 33, as long thread-like filaments from the bases of the dorsal cirri, continuing to near posterior end of body.
Pygidium with two long thread-like cirri.
Proboscis with a pair of wing-like mandibles. Maxillae with short oval carriers. Maxillae I: hooked forceps; maxillae II: 12-17 teeth each; maxilla III: 8-18 teeth; maxillae IV: 4-11 teeth each; maxillae V with a single tooth.
Up to 215 mm for 180 segments.
Cylindrical, transparent, quill-like, marked by faint rings; both ends guarded by usually three pairs of membranous valves.
On all types of substratum from the intertidal zone to depths of more than 4000 m. The tube, in which the worm lives, lies on the surface; the worm protruding from the tube and dragging it around.