28 



material does not suffice for an analysis of the distribution of hyperi- 

 ideans in this region. 



In the Atlantic Ocean, most Physosomata are found in tropical 

 regions, although some enter northern regions by means of warm- 

 water currents. Such, for example, are Lanceola felina, Mimonectes 

 sphaericus, M. loveni, Proscina magna, Scina curvidactyla, S. vosseleri, 

 S. oedicarpus, S. lepiima, and some others. Only a few species 

 are adapted to just the temperate cold-water regions of one or 

 both hemispheres. These are Archaeoscina steenstrupi, Megalanceola 

 stephenseni, and Proscina stephenseni. However, it must be noted that 

 despite a large number of expeditions, the Physosomata fauna of the 

 Atlantic Ocean has not been sufficiently studied. More information is 

 available only for tropical regions. 



The Physosomata fauna of the Southern Ocean has been studied so 

 little that there is no basis for drawing conclusions about its local charac- 

 teristics. It can only be emphasized that the Southern Ocean contains just 

 a small number of endemic forms {Paralanceola anomala, Mimoscina 

 setosa), which do not penetrate the lower latitudes. On the whole, as seen 

 from Table 3, this fauna is more depauperate than that of the northern 

 regions of the Pacific and Atlantic oceans, but obviously this is largely 

 due to inadequate study. 



The unique hydrological conditions of the deepwaters of the Central 

 Polar Basin differ sharply from those in oceanic deepwaters and deter- 

 mine its overall paucity of deepwater fauna (Vinogradov, 1968). Such 

 conditions exert a strong influence on the deepwater hyperiidean fauna, 

 which is represented by only two eurybiontic species: Lanceola clausi 

 and Scina borealis. 



Infraorder Physocephalata 



The ecological diversity of taxa comprising the infraorder Physocephalata 

 makes an overall analysis of its geographic and vertical distribution less 

 feasible. Hence we shall individually describe each constituent of the 

 superfamilies Vibilioidea, Phronimoidea, and Platysceloidea. 



The superfamily Vibilioidea (families Vibiliidae, Cystisomatidae, 

 and Paraphronimidae) includes only 27 species. These are mostly rep- 

 resentatives of the mesopelagic, although the Cystisomatidae are found 

 in the bathypelagic down to a depth of 2,000 m and more, and some 

 Vibiliidae inhabit surface water layers. 



Many Vibilioidea are known for their extensive, often panoceanic or 

 circumoceanic range (more than 50% of the species), but not one species 

 is found in the Central Polar Basin (Table 5). Nearly 30% of the species 

 of this superfamily and all those of the genera Vibilia and Paraphronima 

 are found throughout the entire remaining oceanic water bodies. Species 



