20 GUSTAF EISEN, ON THE ARCTIC OLIGOCHJETA. 



however soinewhat lesscned by its varying to a certain exterit in all forms of this sec- 

 tion of the genus. 



o v 



6. Arckienchytranis ochraceus n. sp. 



Pl. V. Fig. 9. 



The supra-cesophagial ganglion is very mueh like that of tiie preceding species, 

 only tlie emargination of the posterior margin being perhaps a little deeper (fig. 9. d). 



The vesicle of the efferent duct is bent or perhaps rather screwlike. The penis 

 is smaller than in A. g emmatus (hg. 9. g). 



The receptacle is largest in the middle, from where it tapers towards the top, 

 which is bent, generally close to the middle part of the organ (fig. 9. f). 



The inner tube of the segmental organs runs in a line with the outer tube which 

 is longer and more narrow. The middle lobe is transversely wrinkled. 



The ovaries are in the 1 l th and 12 th segments (fig. 51). 



The testes are in the 8 th , 9 th and 10 th segments (fig. 51). 



The length of the body about 15 m. in. 



The width of the body about 1 m. m. 



The number of segments about 52. 



The perigastrie cells are very large and round with a plain nueleus, as in most 

 species of this section of the genus. 



The spines about 5. 6. 6. 5., the inner ones being a little shorter. 



Habitat. Novaja Sendia at Cape Grebenij and Waigatsch. Only a few specimens 

 were found. 



The principal character of this species is derived from the comparative length 

 and location of the inner tube of the segmental organs, which is in fact the only 

 constant character by which it is distinguisbed from the following species. 



7. Archienchy trams uasutus n. sp. 



Pl. VI. Fig. 10. 



The supra-cesophagial ganglion is broader than long, and its posterior emargina- 

 tion is not very deep. The whole posterior part of the ganglion is much rounded. 



The receptacle consists of three parts nearly equal in length: the tube, the recep- 

 tacle proper, and a long narrow säck, generally bent at the top of the former. The 

 top of the tube or the bottom of the receptacle proper is always convex (fig. 10. e). 



The vesicle of the efferent duct resembles a bagpipe, the upper part being 

 the largest and bent över. The opening of the vesicle is surrounded by a curious 

 ring (fig. 10. f and g) of a peculiar shape. 



The segmental organs are large, and the inner duct is of the length of the middle 

 lobe, towards which it is closely pressed (fig. 33). 



The ovaries are placed in the ll th and 12 th segments. 



