162 



PART II. SYSTEMATIC ACCOUNT 



"The preannular part of the trunk contains spermatophores which are 

 0-85 mm long and spindle-shaped. When the filament is removed the 

 filamentar end of the spermatophore is seen to be flattened and drawn out 

 into 2 flaps, which are usually folded inwards (Fig. А92Я). 



"The tube is black and completely opaque, and was 25 cm long before 

 being broken to remove the animal. The diameter of the tube varies along 

 its length from 0-5 to 0-9 mm. The wall is stiff and is made of several layers 

 of brown material with a transparent lining layer; its outer surface has narrow 

 raised rings at fairly regular intervals (Fig. A92A). 



"0. ivanovi differs from 0. dogieli in having plaques on the trunk papillae, 

 and in this respect it resembles Birsteinia vitjasi and confirms Ivanov's 

 hypothesis that the 2 genera are closely related. The spermatophores of 

 Oligobrachia dogieli and 0. ivanovi both have wing-like flaps at the filamentar 

 end while there are no such flaps in Birsteinia or any other pogonophore yet 

 described. Other characters in common between the 2 species of Oligo- 

 brachia are the curious patches or spots on the tentacles, and the compara- 

 tively long pinnules. The tentacles in Birsteinia have very short pinnules and, 

 apparently, no spots or glands of any sort (Ivanov, 1952a)." 



Material: one male, lacking most of the postannular region. 



Locality: off the mouth of the English Channel (48°26'N 10°8'W). 



Depth: 1335-1425 m. 



Table Al 

 Characteristics of the species of Oligobrachia 



2. Genus Nereilinum Ivanov, 1961 



Ivanov, 1961a: 388; Ivanov, 1961b: 138-9. 



The genus consists of Oligobrachiidae with two tentacles and a pronounced 

 secondary metamerism of the metasomal pyriform glands. These glands, at 

 the anterior end of the metasoma, are not set in papillae. The bridle is simple 



