SIBOGLINUM NORVEGICUM 



251 



of the keels of the bridle, the absence of a glandular girdle, and the structure 

 of the tube. 



Material : masses of tubes, some with animals and some empty. 



Locality: the Bering Sea, to the southeast of Cape Olyutorski (60°N 

 170°20'E). 



Depth: 3740-3802 m. 



Fig. 125. Siboglinum minutum: A - spermatophore ; В - middle part of tube; С -hind part of tube. 

 (After Ivanov, 1957a.) 



21. Siboglinum norvegicum Ivanov (Fig. 126) 



Ivanov, 1960c: 5, 27, 127, 183-6, 197, 265, Figs. 87, 126. 



The presence of Siboglinum in the northern part of the Atlantic Ocean, in 

 the Norwegian Sea, is of great zoogeographical interest. In 1958, the Polar 

 R.V. Sevastopol found tubes of several species of Siboglinum on the conti- 

 nental shelf near the Shetland Isles, in the eastern part of the sea, and, 

 in deeper water, to the east of the coasts of Iceland. In these collections, 

 the tubes most frequently encountered were characteristic delicate trans- 

 parent tubes, with regular rings, belonging to none of the few known Atlantic 



