THE MARINE MOLLUSCA OF THE KERMADEC ISLANDS IN 



RELATION TO MOLLUSCAN FAUNAS IN 



THE SOUTH WEST PACIFIC 



By R. K. Dell 



Dominion Museum 

 Wellington, New Zealand 



The demarcation and nomenclature of Australasian and South- 

 West Pacific biogeographical regions have been largely a matter of 

 rather haphazard incremental growth. Whitley (1932, p. 167) published 

 a map showing the Australasian regions based upon studies by Hedley 

 Iredale, May, Hull, Finlay, and Cotton. Unfortunately the journal in 

 which Whitley published is not widely known overseas, and the com- 

 pilation he so adequately presented does not appear to have attracted 

 much notice. The Schilders, for example, (1938-39) in their monu- 

 mental study of the Cypraeidae either did not know of Whitley's 

 scheme (or any of the previous work on Australasian faunal regions) 

 or ignored it. Iredale and Allan (1940, p. 445) published a map 

 showing "former Zoological Land connections with Lord Howe Island" 

 which, together with their text, implies some interesting modifications 

 of Whitley's scheme and indicates the probable origins of the fauna! 

 regions. 



In the meantime, Powell has added a northern faunal zone to the 

 Neozelanic region, the Aupourian (Powell 1937, p. 156; 1940, p. 205). 

 There is little difficulty involved in delimiting the broad faunal 

 provinces of New Zealand and Southern Australia (though the actual 

 boundaries have not been determined in a number of cases). But the 

 Dampierian (Western and North-western Australia) and Solanderian 

 (Great Barrier Reef) and New Caledonia, Lord Howe, Norfolk, and 

 the Kermadec Islands are on the outskirts of the widespread Indo- 

 Pacific marine fauna and are influenced to a varying extent by it. The 

 truly marginal areas of Lord Howe, Norfolk, and the Kermadecs have 

 always presented problems of classification. Each can quite easily be 

 considered a distinct faunal province but the determination of the bio- 

 geographical region to which each belongs has proved difficult. 



In the belief that study of these marginal areas may throw consider- 

 able light upon the methods to be used in subdividing the Indo-Pacific 

 marine fauna, the marine mollusca of the Kermadecs have been sub- 



499 



