20 THE GEOGRAPHY OF MAMMALS 



(Mice), all of which, except the wide-ranging Mus, are 

 confined to this Region ; the only other Rodent that occurs 

 in it is the Javan Porcupine, which has just crossed the 

 dividing-line between the Oriental and Australian Regions 

 into the islands of Flores and Sumbawa. 



The Bats of the Australian Region (3) are very numerous, 

 more especially in the islands to the north of Australia, 

 where the tropical conditions are specially favourable to 

 the development of this group. No less than twenty-eight 

 genera, containing nearly one hundred species of Bats, are 

 met with within the Region, and of these genera eight are 

 not found elsewhere. This is a high percentage, only 

 excelled in the Neotropical Region, which is extraordinarily 

 rich in Bats, having no less than forty-two out of forty- 

 seven genera confined to it. 



The five other Orders of terrestrial mammals — the 

 Ungulata, the Carnivora, the Insectivora, the Edentata, 

 and the Quadrumana — may be considered as practically 

 absent in the Australian Region, though members of 

 several wide-ranging genera have just crossed the line 

 of separation, and are represented in some of the islands 

 on the north of Australia; but, with the exception of 

 the Dingo, none of these reach the actual continent of 

 Australia. 



The question of the origin of the Dingo has not yet 

 been settled. Although fossil remains of this animal 

 have been found in the recent Tertiary deposits, it is 

 difficult to say whether the Dingo was introduced into 

 Australia by the aborigines or is indigenous. At the 

 present time it appears to be found both in a wild state 

 and in a semi-domesticated condition among the native 

 Australians. 



