GENERAL CHARACTERISTICS OF FAR EASTERN SEAS 



737 



Fig. 361. Extent of taxonomic isolation of deep-water bottom-living fauna of the 



northern and southern halves of the Oceans. The lower chart for depths less than 



2,000 m, upper chart for depths more than 4,000 m (Vinogradova). 



horizontal distribution. It is most remarkable that the deep-water fauna is to a 

 great extent both bipolar (Fig. 362) and amphi-boreal in its distribution. The 

 circumtropical distribution of many members of the deep-water fauna also 

 needs some explanation. What factors restrict its distribution southwards 

 and northwards? 

 Change of pressure may restrict the upward and downward movements of 



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