152 BARBOUR: ZOOGEOGRAPHY. 



stronj^iy now, and which has never been adequately touched upon, is the extreme 

 difference between New Guinea and Australia. We notice at once that a large 

 proportion of the anima's which have previously been cited as being common to 

 New Guinea and Australia, though they may occur widespread through Papuasia 

 are confined in Australia to the Cape York Peninsula region. Numberless ex- 

 amples of this sort of distribution are found among birds, reptiles, amphibians, 

 and many other groups. Only one hypothesis can possibly explain tliis. The 

 Gape York Peninsula of Australia formed an integral part of Papua for a long 

 time; for almost as long it must have been cut off from the rest of Australia. 

 The other part of the continent developed what we now know as the true Aus- 

 tralian fauna, probably derived in great part from Antarctis; and just before 

 the Torres Strait break took place, the region of the Cape York Peninsula became 

 joined to the rest of Australia; thus a certain number of Australian creatures 

 got into Papuasia, and ultimately reached the Solomon Islands on the one hand, 

 and Celebes on the other, by the land connections which still persisted in these 

 two directions. Thus we have an Australian element in Papuasia, but not a 

 Papuan element in .Australia, — the opposite of what Suess maintains (4, p. 668). 



F. C. Muir, who has done extensive collecting in British New Guinea and 

 in Upper Queensland, arrived independently at very similar views; with his 

 permission I quote the following from one of his recent letters : — 



"The Eucalyptus is a characteristic Australian plant, and goes into New 

 Guinea and the Malayan Islands. But whereas in Australia it is the home of a 

 very large and peculiar insect fauna, in New Guinea and the Malay Islands it is 

 nearly destitute of insects. Australia is very rich in short-tongued bees. One 

 can collect many any day ; but in New Guinea and the Malayan Islands they are 

 comparatively rare, — the Rhynchota of Fiji are far more Papuan than Australian. 

 To anyone who has collected in British New Guinea and Queensland, the differ- 

 ence is very striking indeed." 



Muir then continues: — 



"My opinion is that the Australian fauna and flora arose in western Australia 

 when it was separated from east Australia. In those days east Australia was a 

 long, mountainous island, divided from west Australia by a sea, and had a heavy 

 rainfall. The island had then a distinct Malayan facies. When the land rose, 

 joining east and west Australia, the east became much drier, and the western 

 forms made headway in northern Queensland; and certain spots in southern 

 Queensland and New South Wales, where there are still heavy rains, retain their 

 Malayan facies; but in drier parts it is Australian. New Guinea was cut off 



