84 



CELTIC PKOVINCE. 



more abundant development of the population of 

 the sea, even though its extent be limited by the 

 deleterious influence of the brackish waters that flow 

 from the Baltic. An excellent account of the con- 

 ditions and phenomena of submarine life in the 

 Strait of Oresund, has been published by A. S. 

 Orsted.* This essay should be studied by every 

 naturalist interested in such inquiries. In the lo- 

 cality explored, this able observer distinguishes 

 three regions of submarine vegetation. The first is 

 that of green sea-weed, Regio Chlorospermearum, 

 It extends from the highest sea-mark to a depth of 

 from 2 to 5 fathoms. Its upper portion is the 

 sub-region of Oscillatorinece, and is that part most 

 frequently exposed to the air. Its lower portion is 

 the sub-region of Ulvacece, where the sloke-plants, 

 TJlva lactuca and latissima, with various Confervce 

 and species of Hormiscia, Ulothrix, and Cruoria, 

 flourish. A few olivaceous algse, and some purple 

 ones, but never those that are of brilliant hues, also 

 occur. The second region is that of the olive- 

 coloured seaweed, Eegio Melanospermearum, ex- 

 tending to 7 or 8 fathoms. It is constituted also 

 of two sub-regions ; the uppermost is that of Fucoids 

 and Zostera. " This," remarks the describer, " is, as 

 it were, the savannah of the sea, for the Zostera 

 marina, which, here ruling, has so much of the as- 

 pect of a grass, that the fishermen call it sea-grass, 



* " De Regionibus Marinis. Elementa Topographic Historico- 

 Naturalis freti Oresund." Havnise. 1844. 



