OF MAMMALIA. 597 



assume much the same history of events as above to have 

 occurred in the secondary strata of Europe, America and 

 Africa, and possibly in the Eocene of America. The 

 Mo?iotremata have, however, had to compete with the 

 Metatheria even in Notogoea and have only survived in 

 small numbers. 



It is well to note that the regions of Notogoea form more 

 or less of a gradation. (i) Polynesia has practically an 

 oceanic fauna and there are no mammals but bats. (2) 

 New Zealand is equally bare of mammals but has more 

 reptiles and birds. (3) Australia has Prototheria and 

 Metatheria wath a few incidental Eutheria. (4) Austro- 

 Malaysia has more Eutheria^ e.g., the pig, and approximates 

 to Eurasia in faunistic character. The best line of separa- 

 tion between Notogoea and the rest of the world would 

 pass to the east of Celebes, but the demarcation is merely 

 arbitrary. The. chief point about the mammalian fauna of 

 Notogoea is that it essentially belongs to the two lowest sub- 

 classes to the almost entire exclusion of the third. The 

 assumption in explanation is that Notogoea has been isolated 

 from the rest of the world before the evolution and spread 

 of the last sub-class, but not before the two lowest sub- 

 classes had spread downwards from the north. 



Extant Mammalia of Notogoea. 



SUB-CLASS. ORDER. FAMILIES. 



Prototheria Monotremaia 2 (Duckmoles, Echidnae.) 



Metatheria Diprotodontia 3 (Kangaroos, wombats, 



phalangers.) 

 Polyprotodontia 3 i r (Dasyurus, bandicoots, 



marsupial-mole?. ) 

 Eutheria Rodentia i 7 Species. 



Carnivora i i 



Ungulata i i 



Chiroptera 5 Large number. 



2. Neggcea. — This realm contains the remainder of the 

 sub-class Metatheria^ not found in Notogoea. These are the 

 opossum-rats and the opossums, representatives respectively 

 of the orders Diprotodontia and Polyprotodontia. Of the 

 Eutheria there is no lack in point of numbers. It has a 

 monopoly of one sub-order, the Xenarthra, or sloths, anteaters. 



