On the high boreal intertidal zone of Europe, we do not find 

 Littorina neritoides or Ligiidae. On the rocky intertidal zone of 

 I'lurnian, _L. saxatil is dominates, the amphipod Hyale prevosti and oli- 

 gochaetes are seen. In surf habitat, usually the green algae (primarily 

 Urospora penicill ifonnis ) , blue-green alagae and a few Porphyra 

 umbil ica'l is are found (K^ssakin, 1953). The biomass of algae here is 

 usually not over 200 g/m^, of animals--! g/m^. On the rocky intertidal 

 zone of Kurman, the biomass of algae (Ulothrix pseudoflacca and 

 Spongomorpha sp.) decreases to 30 g/m^, the biomass of animals increases 

 greatly--to 150-650 g/m^--due to the increase in the number of _L. 

 saxatil is (up to 1600 indiv./m ) and the appearance of a large number of 

 amphipods, primarily Gammarus oceanicus (>10,000 indiv./m ). 



In the northern Pacific in the boreal zone, very similar 

 communities are developed with predominance of J., si tchana , J^. kurila 

 and L. mandschurica , gradually replacing each other in that sequence 

 from north to south. On littoral cliffs of the Kurile, the density of 

 Littorina kurila reaches 15,000 indiv./m^, with a biomass of up to 2 

 kg/m^, while in rocky littoral areas we find up to 100,000 indiv./m^, 

 with a biomass of up to 15.5 kg/m^. 



In the subtropical and tropical latitudes, in addition to the genus 

 Littorina , we also find other representatives of the family 

 Li ttorinidae-- Melarapha , Nodil ittorina , Granul ittorina , Tectarius , 

 Echinella, Peasiella, Echininus and Bembicium. Sometimes, several 



species of Littorinidae form independent bands at the supral ittoral 

 edge. For example, in Tanabe Bay (Japan), bands of Nodil ittorina pyra- 

 midal is , H_. granularis , _N. picta , Littorina brevicula and, finally, 

 Peasiella roepstorff iana follow in sequence from top to bottom (Habe, 

 1958) . Tn addition to the Littorinidae, the Neritidae and Grapsidae 

 crabs are also characteristic. 



The littoral system per se . This system, in places with moderate 

 or weak surf, is usually located between the mean levels of high water 

 and low water springs or tropical tides and occupies a large portion of 

 the intertidal zone. The population of this system is significantly 

 more varied than that of the supral ittoral edge, but here also we 

 encounter only a few formations over a considerable area, flost charac- 

 teristic are the barnacles (Chthamalus , Balanus , Tetrad ita , Elminius , 

 Lithotrya , Ibla , Octomeris , etc.), limpets Tecturidae, Patelidae and 

 Si phonoari idae, the predaceous gastropods Thaididae, the mussels 

 Mytilidae ( Mytilus , Brachyodontes , ffediolus , Septifer , etc.) and the 

 Ostreidae (Ostrea , Crassostrea , etcT) and the Grapsidae. Usually here 

 we also find Littorinidae and Neritidae, particularly in the upper 

 portion of the system, but here they are rarely among the dominant 

 species. In places, the polychaete Serpulidae or Sabellidae, sea 

 urchins ( Paracentrotus , Strongylocentrotus , etc.), ascidian Pyura , etc., 

 may predominate. Among the algae, the green, brown, and red are well 

 represented. In temperate waters, the brown algae usually predominate-- 

 the fucoids (in the North Atlantic Fucus , Pelvetia , Ascophyllum , in the 

 northern portion of the Pacific Ocean Fucus , Pelvetia , Pelvetiopsis , in 

 the southern hemisphere Hormosira ). In warm seas, the red algae usually 

 dominate, and in temperate waters they are numerous in the lower 

 intertidal zone. 



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