NEREILINUM MURMANICUM 163 



and its keels lack any accessory rodlets. There are no adhesive plaques. 

 The postannular region of the metasoma bears metameric ventral papillae 

 and dorsal shields. The tube is ringed but not segmented. 

 There is a single species, the type of the genus : Nereilinum murmanicum. 



1. Nereilinum murmanicum Ivanov, 1961 (Figs. B,C,D, 92) 



Ivanov, 1961a: 381-388, 396, Figs. 1-3; Ivanov, 1961b: 138, Fig. 1 ; Moskalev, 1961. 



Pogonophora have recently been discovered in the Barents Sea (Moskalev, 

 1961) near to the Murmansk Institute of Marine Biology, where they have 

 been kept alive in the laboratory. Material sent to me from this laboratory 

 proved to be a new species which was named Nereilinum murmanicum. 



The body is slender, no more than 0-32 mm in diameter. The fore-part of 

 the body is cylindrical and smooth with a length to breadth ratio of 6 : 1 to 

 10 : 1 according to the degree of contraction of the body (Fig. B92). The 

 bridle is placed at the end of the first third of the fore-part of the body. The 

 groove between the protosoma and the mesosoma runs straight across 

 the ventral side but dorsally it turns backwards to meet the dorsal ends of 

 the keels of the bridle (Fig. B92A, В, C). The protosoma is thus much longer 

 on the dorsal than on the ventral side. The small conical pointed cephalic 

 lobe is not separated from the protosoma by any groove. Two tentacles are 

 attached halfway between the anterior tip of the body and the hind end of 

 the protosoma. They are long and delicate and lack pinnules. The epidermis 

 of the tentacles is rather thin. The bridle is furnished with simple thin 

 brownish keels which join on the ventral surface and just fail to meet dorsally. 

 The epidermal ridges of the bridle are narrow but readily visible. Behind the 

 bridle and in contact with it is a half ring of glandular tissue which is broken 

 on the ventral side. In the majority of specimens the dorsal and ventral blood 

 vessels and the round epidermal glands of the mesosoma are visible by 

 transparency. The glands are only to be found behind the bridle where they 

 form a more or less regular avenue on either side of the mesentery (Fig. 

 B92C, D). The boundary between the mesosoma and metasoma is marked 

 by a simple circular groove (Fig. B92). 



The well-marked ventral sulcus of the anterior part of the metasoma is 

 flanked by a pair of latero-ventral epidermal ridges inside which the clear 

 pyriform glands can be seen by transparency. There are no adhesive papillae 

 or plaques, and the glands are distributed in a rather haphazard manner, 

 especially in the anterior region, where they usually are ranged two or three 

 deep (Fig. В92Л, D). Farther back, however, in certain specimens they be- 

 come gradually more regular in their distribution, becoming reduced to a 



