THE EUROPEAN SEAS. 



273 



extent, it may be asked, have the Mediterranean 

 and Red seas a community of specific forms ? 



This question has been partly answered by Phi- 

 lippi, to whom the Red Sea shells collected by 

 Ehrenberg and Hemprich were referred for exami- 

 nation. He found that out of 382 shell-bearing 

 Mollusks, as many as seventy-four were also com- 

 mon Mediterranean species. This appeared to be 

 a somewhat large proportion, and, for the pur- 

 pose of explaining it, some naturalists adopted the 

 supposition of a communication between these two 

 seas at some former period. This notion has had 

 considerable weight given to it by some expressions 

 of M. Deshayes in his notice of the Mollusca of the 

 coasts of Greece. M. Deshayes, however, admits 

 that the more the shells of the Mediterranean are 

 studied, the closer becomes their connection with 

 those of the Atlantic ; so that it is rather by means 

 of the fossil shells found in the older Mediter- 

 ranean sea-beds, and which now form part of the 

 lands of Greece and Italy, that this eastern con- 

 nection is to be traced. 



Certain species of Mollusks are so cosmopolitan 

 that a low proportion of common forms may be ex- 

 pected even between two remote provinces, and will 

 not constitute any difficulty as to the existence of 

 Zoological provinces generally. A reference, how- 

 ever, to the list of species common to the Red Sea 

 and the Mediterranean will suggest, both that the 

 number may be somewhat modified, and also that 



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