THE EUROPEAN SEAS. 



157 



noticed, that several other outlying forms of northern 

 types have also been met with. 



Amongst the Mediterranean Crustaceans, there is 

 found a species of Mitlirax. The genus is character- 

 istic of the western or American side of the At- 

 lantic. When we consider the pelagic habits of some 

 of the Crustacea, we might expect a much greater 

 amount of agreement between the remoter portions 

 of wide seas or oceans, so far as these animals are 

 concerned, than could be looked for in the distri- 

 bution of the Mollusca or even of the fishes : of all 

 marine animals, certain Crustaceans are the most 

 oceanic ; the central Atlantic regions of the floating 

 weed-banks swarm with them. It will not, there- 

 fore, surprise us to find that the Crustacea of the 

 Atlantic islands present an assemblage which departs 

 a little from the Lusitanian character of the fauna 

 of that group. Of forty-three species, more than 

 half are also Mediterranean, and a few Celtic and 

 Lusitanian, as Inachusdorynchus ; but the distinctive 

 character of the assemblage is derived from the 

 southern forms. Grapsus strigosus and Messor, 

 marginal crabs, are abundant, as is Plagusia clavi- 

 mana ; these range down the African coast into the 

 Southern and Indian Oceans, and occur in the Red 

 Sea. The " Sea-spider," Leptopodia sagittaria, is 

 common to the Canaries and the West Indian 

 Islands. 



The Tunicated Mollusks have not as yet been 

 alluded to in the notices of the northern Atlantic 



