502 EIGHTH PACIFIC SCIENCE CONGRESS 



evidence of a former land connection (possibly quite early in the Ter- 

 tiary) but a number of the mollusca may quite well have been derived 

 at a later period by transoceanic migration. The slight Australian 

 element could also have been similarly derived. Geographical propin- 

 quity coupled with direction and intensity of ocean currents can be as 

 important as a land connection in the past. 



Almost a tenth of the molluscan fauna of the Kermadecs are 

 pelagic in habitat, but this is a sign of the comparative paucity of the 

 molluscan fauna. On the other hand quite a large percentage of the 

 Indo-Pacific mollusca present at the Kermadecs will probably prove to 

 have highly motile larval stages. 



The figure shows in simplified form the probable relationships of 

 the marine molluscan faunas of the various land masses in the South- 

 west Pacific and points up the difficulty of assigning any of the isolated 

 areas to a neighbouring biogeographical area. The answer to the prob- 

 lem may well be to designate a South-West Pacific biogeographical 

 region with a large number of subregions, e.g., Kermadecian for the 

 Kermadec Islands, Philippian for the Lord Howe and Norfolk Islands, 

 Neozelanic for the New Zealand and Australian, and Montrouzierian 

 for New Caledonia with subdivision into provinces v/hen necessary (e. 

 g. Australia and New Zealand). 



Bibliography 



Iredale, T. and J. Allan, 1940. A Review of the Relationships of the Mol- 

 lusca of Lord Howe Island. Austr. ZooL, vol. 9, pp. 444-451. 



Powell, A. W. B., 1937. New Species of Marine Mollusca from New Zealand. 

 Discovery Reports, vol. 15, pp. 153-222. 



Powell, A. W. B., 1940. The Marine Mollusca of the Aupourian Province, 

 New Zealand. Trans. Roy. Soc. N.Z., vol. 70, pp. 205-248. 



ScHiLDER, F. A. and M. Schilder, 1938-39. Prodrome of a Monograph of 

 Living Cypraeidae. Proc. Mai. Soc, vol. 23. 



Whitley. G. P., 1932. Marine Zoogeographical Regions of Australasia^ 

 Austr. Nat., vol. 8, pp. 166-167. 



