177-238 Ophiopenia tetracantha + Ophi- 

 fine ura sarsi + Verticordia nadina 



sand —Amphioplus macraspis 



and mud 

 340 Heliometra glacialis maxima + 



Ophiura sarsi + Verticordia na- 

 dina 



derms 

 158 Echinoderms form more than 

 half of biomass 



242 Biomass formed almost 

 clusively of echinoderms 



ex- 



numbers of species of Foraminifera are fifty- two, nine and three (14 in the 

 Sea of Okhotsk). This is much less than in the neighbouring Okhotsk and 

 Bering Seas (O. Mokievsky, 1954). It is well known that the true deep-water 

 fauna is absent from the abyssal in the Sea of Japan. The most eurybathic 

 sublittoral organisms descend into it. The youth of this faunal group is re- 

 flected in the fact that it has not yet had time to acquire an endemic character. 

 Only very few deep-water forms can be called endemic (the polychaetes Har- 

 mothoe derjugini and Tharix pacifica ; the echinoderms Pedicillaster orientalis; 

 and the crab Chionoecetus angulatus bathyalis). At the same time a large 

 number of eurybathic species with a wide vertical habitat live in the depths 

 of the Sea of Japan (the polychaetes Capitella capitata, Maldane sarsi, Tere- 

 bellides stroemi, Artacama proboscidea, Harmothoe impar, Spiochaetopterus 

 typicus, Chaetozone setosa; the molluscs Thyasira flexuosa; and the echino- 

 derms Ctenodiscus crispatus and Ophiocantha bidentata). All these forms are 

 also widely distributed in the Arctic seas. 



Boreal forms also live in the depths of the Sea of Japan (the polychaetes 

 Notoproctus oculatus, Aricidea succica; the crustaceans Nicippe tumida, 

 Urothoe denticulata, Nectocrangon dentata, Eualus biwiguis; the molluscs 



