THE EUROPEAN SEAS. 



237 



tional ones, and the degrees in which provinces will 

 differ, will depend on whether their number be large 

 or small. 



Mr. Woodward considers that a province should 

 have one-half of its species peculiar to it. If sub- 

 jected to this test, our proposed European provinces 

 are certainly too numerous ; but though they may 

 not be such as the rigid naturalist requires, and 

 even may not present sufficiently broad characters 

 to satisfy the general reader, they will still, in some 

 respect, be found convenient. Strictly speaking, the 

 Lusitanian and northern provinces alone comply 

 with the rule as to proportion of peculiar species — 

 so that the Celtic province, which is established on 

 the mixed and intermediate character of its fauna, is 

 not of like value with the others. 



A province is distinct so far as it is supposed to 

 contain a certain amount of specific forms which 

 have not been found in some other part of the 

 same sea or ocean, but it has never any stronger 

 support than that of negative evidence. 



The northern limit of the Lusitanian province 

 seems to have been indicated by Ed. Forbes, when 

 he states, " that the collector in search of a complete 

 series of British shells, would have to go to the 

 Channel Islands for those forms which, though in- 

 cluded in our list, are almost extra-British." Since 

 this was written the Lusitanian species, which have 

 been ascertained to range as high as the prolific 

 coasts of this group, have been somewhat increased, 



