y^ ANNELIDS. I. 



to be found, either in this respect or to justify the establishment of any variety, to say nothing of 

 nova species. In all essentials .it agrees with the typical H. Sarsi, and only a few small differences 

 can be stated. 



The specimen, intermediately captured, is 20 mm. in length and 7 mm. in breadth, bristles 

 included. The colour is rather peculiar; every Elytron, which is moreover weekly pigmented, has about 

 in the middle a sharply restricted, in form irregular, black spot. 



Each of the elytrophores has on its cephalic side a pigmented spot, and in those parapodia which 

 carry a dorsal cirrus is found, medial to this latter, a prominence pigmented all over the surface, save a 

 distinct line abreast of the animal. 



While the shape of the setee in the whole is typical, some small differences are found. In the 

 Jan Mayen specimens the distal part of the capillary setse is beset with fine hairs arranged in two rows, 

 a feature which gives them a feather-like aspect; these hairs seem to be lacking in the intermediate captured 

 specimen. The broader ventral seta; in the specimens from Jan Mayen are beset with rather delicate, 

 hairy spines, which successively grow smaller towards the tip. The corresponding setae in the pelagic 

 captured specimens have fewer and larger spines that are lacking in the distal part of the bristle, 

 which is here quite smooth. 



Not considering the above mentioned pigmentation in spots, there is scarcely anything to 

 indicate epitokism. The parapodium and the setae do not in the least justify the supposition of a 

 greater ability in swimming by the intermediate captured specimen than by the rest. 



As I thought that it could be of some interest to see how the Baltic form of this species 

 behaved, I examined more thoroughly a specimen taken west of Ronne (at Bornholm) in a depth of 

 46 m. The specimen in question is considerably smaller than the Arctic specimens in general; the 

 length is 15 mm., the breadth c. 6 mm. The pigmentation on the scales is more uniform, darkest along 

 the caudal edge. The pigmentation of the body corresponds tolerably to what has been described 

 above, there is a plain pigmentation on the front side of the elytrophores and of the prominence over 

 the dorsal cirrus. Besides this is seen a pigmented transverse line over the dorsum of the body bet- 

 ween each of two segments, while the segments themselves show a more diffuse pigmentation, separa- 

 ted from the intersegmental line by an unpigmented part. The bristles agree more with the bristles 

 of the pelagic taken specimen than with the features described in the Jan Mayen specimens. 



H. Sarsi is evidently a pronounced Arctic form, which, however, does not appear to be particu- 

 larly common anywhere. In the Baltic, where it is perhaps most frequently found and where it can 

 be taken as far east as at the Alands-Islauds, it must be considered as a relict, as is already 

 expressed by Malmgren. It does not seem to be fond of great depths, thus it is not found on a 

 single Iiigolf-station, and the greatest depth in which it has been taken by the East-Greenland 

 expeditions is 90 fms. However, I must state in this connection that Mcintosh mentions a specimen 

 which is said to have been taken in a depth of 1215 fms. by the Porcupine-expedition. 



