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



level of the sublittoral, and part of the typical littoral forms sink down to the 

 sublittoral. On the western and southern shores of Novaya Zemlya and off 

 the shores of Spitsbergen, where the abrasive effect of ice and the winter cold 

 is not so severe as in the high Arctic region, a very much impoverished flora 

 and fauna can be observed on the littoral. The littoral fauna of the White 

 Sea is fairly varied, it is a somewhat impoverished version of the fauna of the 

 Murman coast littoral ; this latter, however, is very rich. Farther west, along 

 the shores of Norway and the North Sea, the main components of the littoral 

 fauna remain the same but become more varied still, and a number of forms 

 absent in the north are added to it. 



In the Barents Sea the littoral fauna reaches its most luxuriant development 

 on the western Murman coast — on its cliffs, shale deposits, silty sand and 

 sandy mud, in the depth of well-protected fjords, on wide beaches, provided 

 only that their salinity is not too much reduced. 



The littoral fauna is at its richest in the autumn. In winter, owing to the 

 sharp deterioration of climatic conditions, a considerable regrouping of the 

 population of the littoral takes place ; some of it migrates to the sublittoral, 

 some sinks into a quiescent condition. The abundance of light in the summer 

 (the polar day on the western Murman Peninsula lasts from 22 May to 23 

 July) and its absence in winter (the polar night lasts from 30 November to 

 13 January) and extremely sharp seasonal fluctuations of temperature and 

 salinity are characteristic of the Murman littoral. 



For the cliff facies with their overgrowth of fucoids besides Mytilus edulis 

 and two species of Balanus — B. balanoides and B. crenatus — the following 

 animal organisms are likewise particularly characteristic; gastropods: Lit- 

 torina rudis, L. lit tor ea L.palliata, Acmaea testudinalis, Purpura (Nucella) lapil- 

 lus, Limapontia capita ta, Rissoa aculeus; crustaceans: Gammarus locusta, Ido- 

 thea granulosa, Jaera albifrons; Bryozoa: Flustrella hispida, Alcyonidium 

 hirsutum, Sertularia pumilla, and others. All these cliff fauna can be grouped 

 into five basic biocoenoses: (7) Balanus balanoides; (2) Mytilus edulis; (3) 

 Ascophyllum nodosum, Sertularia and Flustrella; (4) red algae and (5) Spha- 

 cellaria with the fauna of worms and small molluscs. 



On the rocky shale, usually partly sunk into the soft sea-bed, among the 

 fucoids, on the sides and lower parts of the rocks and between them and on 

 the floor under them the fauna is usually abundant. Here the most character- 

 istic groups are actinians : Actinia equina ; the sponge : Halichondria tenui- 

 derma ; the nemerteans : Lineus gesserensis and Amphiporus lactijloreus ; the 

 molluscs : Cyamium minutum, and Lacuna ; the crustaceans : Gammarus 

 locusta, G. marinus, Jaera marina ; the fish : Pholis gunnellus and Enchcliopus 

 (Zoarces) viviparus. 



Bryozoa: Flustrella hispida; hydroids: Dynamena pumilla, Gonothyrea loveni 

 and Obelia longissima, O. loveni; three types of Littorina (L. rudis, L. littorea 

 and L.palliata); Balanus balanoides; a large number of molluscs: Acanthodoris 

 pilosa, Dendronotus frondosus, Lamellidoris muzicata and L. bilamellata, 

 Coryphella rufibranchialis, Limapontia capitata; some species of polychaetes: 

 Spirorbis ; and the mollusc Chiton marmoreus settle on the algae. There are 

 some worms in the groups under the rocks, such as Priapulus caudatus, 



