254 BIOLOGY OF THE SEAS OF THE U.S.S.R. 



the brackish-water community, living in large numbers in the diluted waters 

 of the off-shore zones and the river mouths, is of importance. These are the 

 relicts of former eras of more considerable water-dilution and of even more 

 severe climate ; (3) Arctic-boreal species ; (4) Sub-Arctic Barents Sea forms ; 

 (5) The bathypelagic fauna of the central parts of the Arctic basin, which 

 penetrates through the deep troughs on to the continental shelf of the mar- 

 ginal seas of the eastern part of the Arctic ; (6) Warm- water north Atlantic 

 forms, which penetrate into the Kara Sea either directly from the north from 

 the warm intermediate layer of the central part of the Arctic basin, or from 

 the west from the Barents Sea ; (7) Fresh-water forms ; (8) Endemic forms of 

 the Kara Sea ; (9) Cosmopolitan forms. 



Except for the fourth group this division can be applied to the fauna of 

 other seas situated to the east of the Kara Sea. Gorbunov gives the following 

 zoogeographical characteristics for the 97 mass species of the Kara Sea in 

 percentages : 



High Arctic 15 ) _ Arctic-boreal 46 



Pan-Arctic 37 J Cosmopolitan 2 



It should be noted that, among the mass benthos forms, the sub-Arctic 

 and warm-water Atlantic species are not represented. 



