OXFORD UNIVErwSITY SPITSBERGEN EXPEDITION. HID 



Parasitizatiok. 



Finally, I may be allowed to draw atfceiition to the excessive 

 parasitization of most of these worms, which goes much beyond 

 anything that I have previously seen in members of this group. 

 !Not only were there numerous parasites, of more tha,n one group 

 of Protozoa, in the alimentaiy canal, but many of the worms had 

 cysts in the genital region, body-wall, or ccelom, in which spores 

 were forming. It seems probable tliat the frequent structural 

 changes in the alimentary canal, as well as other changes in the 

 contents of the coelom, may be due to this parasitization. 



SYSTEMATIC. 

 Fam. Naidid^. 

 Genus Nais Miill. em. Yejd. 

 Nais josiNtE Vejd. 



Bear Island ; in littoral region of a, tarn near Walrus Bay, in 

 the water; 15. vi. 1921. A single specimen, non-sexual. 



Fam . E N C H Y T R iE I D ^. 



Genus Henlea Mich. 

 Henlea (Henleanella) beleotrophus, sp. n.* 



Spitsbergen ; among mosses on the bank of a fresh-water pond, 

 more or less under water, Bruce City. August lst-8th, 1921. 



Spitsbergen, Bruce City region (no data regarding habitat) ; 

 10.viii.l921. One specimen from each of these tubes. 



Length 8-10 mm. ; diameter '4 mm. Segments 40, with a few 

 more not yet difierentiated at the hinder end. Colour brownish 

 in the first tube, black in the second (fixed with Bouin). Prosto- 

 mium bluntly triangular, the triangle being about equilateral. 

 Head-pore between prostomium and first segment. No doi'sal 

 pores. 



Clitellum on segments xii. and xiii., well marked. 



Setfe enchytrfeine in form {i. e., straight in their distal portion), 

 the tip moderately sharply pointed. In front of the clitellum the 

 ventral bundles have apparently four setfe (not well seen), behind 

 the clitellum 4, 5, 6, and once 7 ; the lateral bundles have usually 

 five setfe, sometimes 4 or 6, in front of the clitellum, and behind 

 the clitellum 4, 5, 6, once 7, and once 8. 



The " taste organ " on the floor of the phaiynx is similar to 

 that described for the nest species, except that its base of attach- 

 ment appears to be a little narrower. 



* 'FAeio-pofos, bred in the marsh. 



