BY CHARLES HEDLEY. 405 



If this arrangement is a natural one, it will be found equally 

 ■applicable to the remainder of the fauna and flora. For I have 

 no sympathy with writers who plot out different ai-eas for different 

 groups of animals and plants with a view to the reconstruction of 

 past continental land. Where the evidence of one group conflicts 

 with that of another, either the testimony or the application is 

 at fault. 



The Route of the Polyiiesimi Fauna. 



Dr. Guppy* has suggested that Polynesia was peopled from the 

 Malay Archipelago by two routes, the one by Micronesia and the 

 other by Melanesia. In the first case, plants and animals may 

 be traced from the Moluccas or the Philippines through the Pelews 

 and Carolines to the Marshalls, and thence down a long chain of 

 archipelagoes, including the Ellice, to the Austral and Paumotu 

 Groups. iJy this route probably came the Pacific rat. In the 

 second case Fiji formed the point of departure, and the invaders 

 passed into Polynesia through Samoa. 



A return current appears to have carried Melanesian forms 

 back to the Carolines, Ladrones and Pelews Evidence of this is 

 given by the occurrence there of Partula, a genus which, as it 

 evidently descended from the Placostyhis stem, undoubtedly arose 

 in Melanesia. 



As the process of populating the Central Pacific Islands by 

 drift from Melanesia is now in progress, it is almost superfluous 

 to remark that both the Papuan and the Antarctic elements of 

 the Melanesian Plateau have contributed to the Polynesian land 

 Mollusca; the former giving Tornatellina, Helicina and Trocho- 

 moryha, and the latter Partula and Endodonta. 



The route of the Polynesia fauna after its departure from the 

 ■continent is too erratic to be exactly recovered. 



Some useful data have been collected by Garrett, who tabulated 

 the range of three families of marine Mollusca through ten archi- 

 pelagoes of the Pacific, as followsf : — 



* (4uppy — Trans. Vict. Inst. 1896. 

 + Garrett— Journ. Conch, i. 1878, p. 356, ii. 1879, p. 108, iii. 1880, p. 8. 



