3^4 



ATLANTIC REGION 



CHAP. 



It has been usual to classify marine Mollusca from moderate 

 depths under the following regions and sub-regions : — 



A. 



Eegions 



Atlantic and 

 Circumpolar 



B. Indo-Pacific 



Sub-regions 



r 1. Arctic. 



2. Boreal. 



^ 3. Celtic. 



j 4. Lusitanian. 



I 5. West African. 



[ 6. South African. 



I 1. Indo-Pacific. 



[ 2. Japanese. 



Eegions 



C. Australian -I 



ri. 



D American 



l2- 

 I 1. 



I 2- 



j5. 



I 6. 



7. 



18. 



Sub-reg-ions 



Australian. 



Neozealanian. 



Aleutian. 



Calif ornian. 



Panamic. 



Peruvian. 



Magellanic. 



Argentinian. 



Caribbean. 



Transatlantic. 



A. The Atlantic Region 



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

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

 circumpolar seas, which may be regarded as roughly bounded by 

 the Aleutian Islands and the coast of Newfoundland. 



(1) The Arctic Suh-region includes the circumpolar 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 

 exclude 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^ Buccinum^ Buccinopsis^ 

 Neptunea. Trophon^ Bela^ Admete^ Velutina^ Trichotropis^ Lacuna^ 

 Margarita^ Philine, Pecten^ Leda^ Yoldia^ Astarte, and Mga. 

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

 rather sombre tint. 



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

 vinces, 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 



