LINNEAN SOCIETY OF LONDON. 87 



related genus Agathis. If statistics carry a meaning, Fagus would 

 seem to have come to Australasia from America, while Ai'aucaria 

 •made the reverse journey. 



The remarkable and well known genus Fuchsia includes sixty- 

 nine species. Four of these are natives of New Zealand, the rest 

 inhabit South America, Mexico, and the AVest Indies. These 

 figures are almost exactly reversed for the shrubby evergreen 

 Veronicas, plants conspicuous in auy New Zealand landscape, 

 totally absent from Australia or Tasmania, and represented by a 

 few stragglers in South America and Fuegia. 



4. Deductions. 



If it be resolved that the community of austral life is explicable 

 •only by former radiation along land-routes from the south polar 

 regions, we reach a position to probe deeper into the intricacies 

 of the problem. 



In the scheme propounded by Dr. H. 0. Forbes, the austral 

 forms inhabited one vast continent, nearly a third of the southern 

 hemisphere, at the same (? Pleistocene) time. But an analysis of 

 the fauna in question shows that some groups avoid Tasmania and 

 others avoid New Zealand. Clearly the Antarctica that supplied 

 Australia with an abundant fauna of marsupials, monotremes, 

 snakes, frogs, and so on, was not in touch with New Zealand, 

 where these animals are conspicuously absent. Benhara has 

 emphasised the fact that the Acanthrodrilids, Antarctic earth- 

 worms, failed to reach Tasmania. When they, the fuschias and 

 other associates, spread backwards and forwards from New Zealand 

 to South America, it is equally clear that the road to Tasmania 

 was barred to them. Iredale remarks (Proc. Malac. Soc. ix. 1910, 

 p. 160) that the Antarctic element in the New Zealand Polyplaco 

 phora, a marine moUuscan group, is distinct from that which 

 reached Tasmania from the south. The differences are both 

 positive and negative, and are not due merely to the more southern 

 latitude of New Zealand preserving a larger proportion of cold 

 types. When circumstances allowed Iguanidae to wander from 

 South America in two genera to Madagascar and in another to 

 Fiji, the Australian road was apparently closed to them. 



It becomes increasingly apparent that the Antarctic source of 

 austral life was not simjile but compound. This complexity hai^ 

 probably beeu the chief hindrance to its recognition. The problem 

 before us is : — Was the complexity that of time or space, or botli ? 

 Shall we suppose, for instance, that at the close of a glacial 

 period an Antarctic continent bare of life received a fauna and 

 flora from one neighbour, then developed and transmitted it to 

 another? That a subsequent glaciation swept all life away from 

 tlie polar area? That a warm interglacial period succeeded when 

 another transfer, but between different neighbours, took place? 



