66 DISCOVERY REPORTS 



The inference is that the present Antarctic fauna is of comparatively recent immigration, probably no 

 earlier than Tertiary times, and that the continuity of the Americas is and has been the chief colonizing 



route. Distribution of Aforia 



Depth 



in fathom 



73 



Temp. 

 °F. 



30-9 



Date 



Species and location 

 insignis (Jeffreys, 1883), 'Icy Sea', Siberia 

 okhotskensis Bartsch, 1945, Okhotsk Sea, 50-60 N 

 kincaidi (Dall, 1920), Shelikoff Strait, Alaska 

 sakhaltnensis Bartsch, 1945, off Sakhalin I. 

 diomedea Bartsch, 1945, Hokkaido, Japan 

 chosenensis Bartsch, 1945, Japan Sea, 40° N 

 japonica (Dall, 1925), Honshu, Japan, 35° N 

 hondoana (Dall, 1925), Hondo, Japan 

 crebristriata (Dall, 1908), south-west of Sitka, Alaska 

 persimilis leonis (Dall, 1908), Washington 

 persimilis blanca (Dall, 1919), Cape Blanco, Oregon 

 amycus (Dall, 1920), off Monterey, California 

 persimilis (Dall, 1889), Cortez Bank, California 

 Gulf of Panama 

 off Panama 

 off Ecuador, i° 03' N 

 south-west coast of Chile 

 goodei (Dall, 1889), north-west Patagonia, 45 35' S 

 goniodes (Watson, 1881), south-east of Rio de Plata, Argentina 



between Falklands and Patagonia 

 staminea (Watson, 1881), off Marion and Prince Edward Is. 



Kerguelen I. 

 magnified (Strebel, 1908), south-west of Snow Hill I. 64 S 



Palmer Archipelago 

 South Shetlands 

 South Sandwich Is. 



The temperatures cited are associated with specimens dredged at various seasons of the year, 

 nevertheless the lowest temperature record, 30-9° F., and the highest, 41-8° F., show a surprisingly 

 small range, with a maximum difference of only 10-9°. That these stenothermic animals go deep over 

 the tropics in order to keep within their temperature requirements is clearly shown by the persimilis 

 records, especially that of the Ecuador occurrence, which at a depth of 741 fathoms and a temperature 

 of 38-4° F. is situated only i° 03' N of the equator. 



BIOGEOGRAPHICAL PROVINCES 



It is not desirable at this stage of our knowledge of southern high-latitude molluscs to formulate 

 a comprehensive scheme of biogeographical provinces. 



A set of quadrant names proposed by Markham (19 12) for the Antarctic and by Waite (1916) for the 

 Subantarctic extensions of these quadrants may be usefully employed for indicating positions and in 

 recording distribution. 



The Antarctic quadrants named by Markham were : 



The Victoria Quadrant: 90 to 180° E 



The Ross Quadrant: 180 to 90 W 



The Weddell Quadrant : 90 to o° W 



The Enderby Quadrant : o° to 90 E. 



