THE EUROPEAN SEAS. 



91 



of the result of their observations on the bathy- 

 metrical distribution of marine creatures, chiefly 

 made upon the coast between Granville and Cape 

 Frehel. They distinguish four littoral belts : a first 

 and highest, dry at ordinary tides, where, when the 

 coast is rocky, barnacles can live, but, if it be sandy, 

 few or no marine animals are found : a second, 

 which, in rocky places, is marked by a population 

 of periwinkles, limpets, Purpura, Nassa, and red 

 actineae ; and where sandy, crustaceans of the genera 

 Talitrus and Orchestes, and the worms Terebella 

 and Arenicola ; when muddy, besides these, occur 

 Nephthis and small siphunculi. The third zone is 

 chiefly characterized by the presence of corallines, 

 and is only uncovered at low tides ; mussels, lim- 

 pets, &c, are found on its rocks, green Actineas and 

 compound Ascidians ; in other places nudibranchs, 

 sea-ears, Polynoes, Serpulce, and Planarice; sponges, 

 lobulariae, and Ascidise garnish the interstices of 

 large stones; millions of small Cerithia and Eissoa 

 live among the grass-wrack, on its softer ground, 

 and cockles, razor- shells, and clams, bury themselves 

 in its sandy mud. The fourth zone, exposed only 

 during the lowest tides, presents tangle-covered 

 rocks, often studded with star-fishes. This is the 

 domain of Patella pellucida; peculiar crustaceans 

 and mollusks of the genera Bulla and Pandora live 

 among the fine sand. At a lower level, never un- 

 covered, is a fifth region, inhabited by oysters, cap- 

 limpets, scallops, many forms of Crustacea, sea-mice, 



