the sublittoral fauna, Pacific elements are absent from it. The bathyal fauna 

 of the central part of the polar basin consists mostly of the pan-Arctic and 

 Arctic boreal forms. 



Collections made by the Sadko in 1935 and 1937-38 give some idea of the 

 abyssal fauna of the central part of the Arctic Ocean north of the Novosibirsk 

 Islands. Members of 98 species were obtained by nine deep-water casts of the 

 trawl at depths of 1,180 to 3,800 m, among them 26 Foraminifera, 4 Porifera, 

 4 Coelenterata, 13 Polychaeta, 1 Pogonophora, 1 Copepoda, 1 Cirripedia, 1 

 Cumacea, 6 Isopoda, 10 Amphipoda, 2 Decapoda, 1 Pantopoda, 19 Mollusca, 

 8 Echinodermata, 1 Pisces, and including also the typical abyssal species like 

 Astrorhiza crassatina and Ammodiscus incertus of the Foraminifera, Myrio- 

 chele danielsseni, Gorbunovia malmgreni of the Polychaeta, Pogonophora, 

 LameUisabella gorbunovi, among Cumacea — Diastylis polaris, among Isopoda 

 llyarachna derjugini, Eurycope ratmanovi, Mesidothea megalura v. polaris, 

 among Amphipoda — Halirages gorbunovi, Melitapallida,3.nd Dulichia cy clops, 

 among Decapoda — Hymenodora glacialis, Bythocaris leucopis, among Mol- 

 lusca — Ganesa bujnitzkii, Natica bathybia, Sipho danielsseni, Tindaria derjugini, 

 Neilonella kolthoffi, Ledella tamara, Propeamussium frigidum, Thyasira otto- 

 schmidti, Lyonsiella Jeffrey si, L. uschacovi, and among Echinodermata — 

 Kolga hyalina. Most of the above-mentioned species are endemic forms of the 

 Arctic Ocean. Besides these forms 20 abyssal species come into the bathyal, 

 and 28 abyssal species were found only in the bathyal. Thirty-seven species 

 caught in the abyssal are immigrants from the sublittoral. The vertical propa- 

 gation of the forms found in the abyssal is given in Table 26. 



A complete absence of bryozoans is a characteristic feature of the Arctic 

 Ocean fauna. Sixty per cent of this fauna is endemic and, of the purely abyssal 

 species, 89 per cent is endemic. 



In Gorbunov's opinion (1946) based on the presence of a number of endemic 



