364 



ATLANTIC REGION 



It has l)een usual to classify marine Mollusca from moderate 

 depths under the following regions and sub-regions : — 



Regions. 



A. Atlantic and 

 Circumpolar 



B. Indo-Pacific 



Sub-regions. 



'1. Arctic. 



2. Boreal. 



3. Celtic. 



4. Lusitanian. 



5. West African. 



6. South African. 

 Jl. Indo-Pacific. 

 y2. Japanese. 



C. Australian 



D. American < 



Sub-regions. 



fl. Australian. 



\2. Neozealanian. 



(I. Aleutian. 



2. Californian. 



3. Pananiic. 



4. Peruvian. 



5. Magellanic. 



6. Argentinian. 



7. Caribbean. 



8. Transatlantic. 



A. The Atlantic Region 



includes the whole of the eastern shores of the Atlantic, from 

 the extreme north to the Cape of Good Hope, together with the 

 circumpolar seas, which may be regarded as roughly bounded 

 by the Aleutian Islands and the coasts of Newfoundland. 



(1) The Arctic Sub-region includes the circmnpolar seas, and 

 is bounded in the N. Pacific by a line drawn between Cape 

 Avinoff in Alaska, and Cape Lopatka in Kamschatka, so as to ex- 

 clude the Aleutian Islands. On the western shores of the Atlantic 

 the cold Labrador current brings it as far south as the coast of 

 Newfoundland, but on the eastern shores the influence of the 

 Gulf Stream has the contrary effect, so that the North Cape may 

 be taken as its southern limit. 



The principal genera (many species of which are common to 

 the whole sub-region) are Volutomitra, Btcccinum, Buccinopsis, 

 N&ptunea, Trophon, Beta, Admete, Velutina, Trichotropis, Lacuna, 

 Margarita, Fhiline, Pecten, Leda, Yoldia, Astarte, and Mi/a. The 

 shells are generally unicoloured, and of a dead white or rather 

 sombre tint. 



(2) The Boreal Suh-region may be subdivided into two 

 provinces — the European and the American. The former includes 

 the entire coast-line of Norway, the Faroe Islands, and Iceland 

 (except perhaps the northern coast), and possibly the Shetland 

 Islands ; the latter the American coasts from the Gulf of St. 

 Lawrence to Cape Cod (lat. 42°). Thus the Boreal American 

 province does not extend nearly so far south as the Boreal 



