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



after bypassing the Barents Sea altogether, and possibly do not meet in the 

 Kara Sea. Owing to the bottom topography the bathypelagic forms of the 

 Arctic basin can penetrate more easily into the Kara and Laptev Seas than 

 into the Barents Sea, except, perhaps, at its most northeasterly corner. 



Among these forms penetrating from the north the following may be noted : 

 Virgularia glacialis and the huge Umbellula ancrinus, reaching 2-5 m in 

 length; the polychaetes Melinnexis arctica, Jasmineira schaudini and Hyalo- 

 pomatus claparedi ; the molluscs Area frdei, Periploma abyssorum, Mohnia 

 mohni; the crustaceans Haplomesus quadrispinosus, Amathillopsis spinigera, 

 Cleippides quadricuspis, Halirages quadridentatus, Rhachotropis lomonossovi, 

 Pardalisca abyssi, Nmmoniscoides ungulatus, Gnathia stygia, Gn. robusta, 

 Eurycope hanseni, Leucon spinulosis, Compylopsis intermedia ; and finally the 

 echinoderms Tylaster willei, Bathybiaster vexillifer, Ophiopus arcticus, Pourta- 

 lesia jeffreysi, Bathycrinus carpenteri, Poliometra prolixa, Elipidia glacialis 

 and others. 



All the three groups range over the Kara Sea, chiefly in its deeper parts, 

 where they mix with the basic Arctic fauna. 



This process occurs intensively along the western trench (St Anna's Trench), 

 which communicates with the Novaya Zemlya Trench at the south. Some of 

 the above-mentioned forms reach the latitude of the Kara Gates through this 

 trench, such as, for example, Ephesia peripatus, Laphania boecki, Amathillopsis 

 spirigera, Bythocaris payeri, while others go only as far as the latitude of 

 Matochkin Shar, as, for example, Jasmineira schaudini, Pardalisca abyssi, 

 Halirages quadridentatus, Poliometra prolixa and others. Moreover, Elpidia 

 glacialis even penetrates into the eastern part of Matochkin Shar. Some of 

 these organisms penetrate southward only up to the latitude of Cape Zhe- 

 laniye and sometimes enter the deep hollow off this Cape, as, for example, 

 Ophiopus arcticus. A large part of this fauna, as, for example, Melinnexis 

 arctica, Eurycope hanseni, Gnathia stygia, Rdiachotropis lomonossovi, Bathy- 

 biaster vexillifer, Pourtalesia jeffreysi and others, when moving south do not 

 go farther than the deep trench between Novaya Zemlya and Wiese Island. 



Gorbunov records a more intensive penetration into the Kara Sea through 

 the western trench than through the eastern. As has been mentioned above, 

 the Kara Sea fauna acquires an original aspect owing to the rising of boreal 

 and abyssal forms — which penetrate the Kara Sea from the north — to shallow 

 depths which are unusual for them. Such deep-water dwellers as Eurycope 

 hanseni, Pardalisca abyssi, Paralibrotus setosus, Erichtonius brasiliensis, 

 Poliometra prolixa, Tylaster willei and others are found here at comparatively 

 shallow depths. 



As we have pointed out, this phenomenon is observed not only with the 

 alien fauna, but also with typical Kara Sea forms which live here at lesser 

 depths than in the Barents Sea; as for example, Hymenaster pellucidus, 

 Ophiopleura borealis and others (Fig. 106). 



The second route for the penetration of fauna from the central part of the 

 Arctic basin into the Kara Sea (the boreal and abyssal forms both of the 

 Arctic basin itself and of the north Atlantic, and the moderate bathymetric 

 Atlantic forms living at moderate depths), passes, as has been shown by 



