Sipunculus (Sipunculus) norvegicus Danielssen, 1869
This species is a small, semi-transparent worm, from cold and deep water. The main distinguishing external character is the posterior glans region that is marked off from the trunk by a ridge.
Types: Museum of Zoology, University of Bergen, Bergen, Norway, ZMUB 1671 (Cutler and Cutler, 1985).
(From Stephen and Edmonds, 1972; Cutler, 1994)
Introvert shorter than the trunk (about a quarter as long as the body). Conical papillae cover the surface.
Trunk is cylindrical, up to100 mm in length, and transparent. The surface of the trunk is divided into a large number of small rectangles by the intersection of the longitudinal and circular muscles.
Glans region (a smooth posterior tip) usually marked off from the trunk by a ridge, and may or may not be interrupted ventrally by a furrow.
Tentacular crown is divided into 8 to 12 lappets or lobes.
20-24 longitudinal muscles bands (LMBs), commonly 21-22.
A pair of short and free nephridia.
Brain is elongated, flattened. The lobes are not prominent, and the processes are not developed.
Ventral retractor muscles originate in LMBs 3 and 4, and dorsal retractor muscles from LMBs 8 and 9.
This is a small species, usually less than 100 mm in length (Cutler and Cutler, 1985).
Ecology and Distribution
Most records are from the North Atlantic, from the equator to 57ºN, but there are scattered records from Red Sea, Mediterranean, Indian, and western Pacific Ocean (Cutler, 1994).
Habitat and Ecology
This species is from deep and cold water from sublittoral and bathyal waters, 100-3000 m (Cutler, 1994).