Sipunculus (Sipunculus) norvegicus Danielssen, 1869
General description:
Types: Museum of Zoology, University of Bergen, Bergen, Norway, ZMUB 1671 (Cutler and Cutler, 1985).
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Sipuncula
Sipunculus (Sipunculus) norvegicus Danielssen, 1869
Sipunculus (Sipunculus) norvegicus Danielssen, 1869
General description: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.
Morphology:(From Stephen and Edmonds, 1972; Cutler, 1994)
External anatomy
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.
Internal anatomy
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.
Size:This is a small species, usually less than 100 mm in length (Cutler and Cutler, 1985).
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:This species is from deep and cold water from sublittoral and bathyal waters, 100-3000 m (Cutler, 1994).