39 



species live in each of these oceans (Table 10). In the Pacific Ocean, only 

 two rare genera, Euscellus and Hemiscelus, are absent; in the Atlantic 

 Ocean, Tullbergella; and in the Indian Ocean, Hemiscelus and Anapro- 

 noe. Apparently, with further investigations, the taxa common to the 

 fauna of different oceans will increase still further. 



The common nature of the Platysceloidea fauna of different oceans is 

 likewise very high, much higher than in all the above-mentioned groups. 

 Nearly 86% of the genera and 68% of the species are common to all three 

 oceans. Between the Atlantic and Indian, Indian and Pacific, and Pacific 

 and Atlantic oceans, 90% of the genera and 70-80% of the species are 

 common (Table 1 1 ). Hence it is absolutely clear that this is the common 

 circumtropical fauna. 



Thus, an examination of the distribution of all major taxonomic 

 groups of the suborder Hyperiidea very clearly reveals a correlation 

 between their bathymetric and geographic distribution. Deepwater 

 species, predominant among the Physosomata, are basically panoceanic 

 or, contrarily, have a narrow local distribution. Eurybathic species 

 inhabiting the epi- and mesopelagic, are characteristic of the 

 superfamilies Vibilioidea and phronimoidea and spread over the 

 temperate-cold-water and cold-water regions of both hemispheres; 

 bipolar distribution is also found among them. Finally, inhabitants of 

 the epipelagic, comprising a large part of the superfamily Phronimoidea 

 and all of the superfamily Platysceloidea, characteristically have a 

 circumtropical or somewhat more extensive distribution, covering central 

 and equatorial waters, as well as circumoceanic areas. 



N 



