KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 15. N:0 7. 17 



finally through its railky colour. The spines are also more numerons in each fascicle 

 and of more equal height. 



2. Archienchytraeus tenellus n. 



Pl. III. Fig. 5. 



The supra-oesophagial ganglion is considerably broader behind and its posterior 

 margin is deeply concave and heart shaped, very much resembling that of the prece- 

 ding species (fig. 5, f.) 



The receptacle consists of a long narrow tube, the length of which is about 7 

 or 8 tirnes its width. The top is sometimes bent, and always considerably more nar- 

 row than the base (fig. 5 g). 



The vesiole of the efferent duct is of the shape of a bagpipe, the ends of which 

 are bent towards each other (fig. 5 h). 



The penis is mnch smaller than that of the preceding species. 



The inner tube of the segmental organs is verv short or of about l j-> the length 

 of the middle lobe, the outer duct on the contrary is of the length of said lobe but 

 much narrower (lig. 28). 



The ovaries in the ll th and 12 th segment (hg. 48). 



The testes in the 8 th , 9 th and 10 th segments (tig. 48). 



The perigastric cells are very large, opaque, round, or oval with a large dirtinct 

 nucleus. Seen from the side they are crescent-shaped (hg. 5 k). 



The segments are about 50, not very well defined. 



The length of the bcdy from 8 to 10 in. m. 



The ■width » » Va m. m. 



The spines in each fascicle 4. 4. 5. 4, very uniform (hg. 5. d). 



The colour is darkgreen behind, and light j^ellow in front of the cingulum. 



Habitat. Collected by the expedition at Sapotschnaja Korga, Jenissej, 71° 40' lat. 



This species is well characterizecl through the presence of numerous large peri- 

 gastric cells, through the absence of the vitreous layer in each segment and through 

 the length and size of the receptacle. 



A form with the receptacle bent at the top and somewhat longer could perhaps 

 be separated as a variety: elongatus (Pl. IV. fig. 5 m). This variety was founcl in Norway 

 near Tromsö, together with Neoenchytrcms Ratzelii, and may be considered as a local 

 variety or a beginning species. 



The supra-cesophagial ganglion of the variety is more narrow in front than the 

 same organ in the typical form, but in other respects they resemble each other perfectly. 



This species and its variety are both characterized by their last segment being 

 considerably swollen, and much larger than the preceding ones. 



K. Sv. Vet. Ak. Handl. lid. 15. N:o 7. " 



