Of the Timor Geoup. 213 



with species inhabiting Java and Australia, there are a con- 

 siderable number of others very closely allied to species 

 peculiar to those countries, and we must take these also into 

 account before we form any conclusion on the matter. It 

 will be as well to combine these with the former table thus : 



In Lombock. In Flores. In Timor. 



Javan birds 33 23 11 



Closely allied to Javan birds 1 5 G 



Total i! ^ iZ 



Australian birds 4 5 10 



Closely allied to Australian birds .... 3 9 26 



Total _I if ^ 



We now see that the total number of birds which seem to 

 have been derived from Java and Australia is very nearly 

 equal, but there is this remarkable difference between the 

 two series : that whereas the larger proportion by far of the 

 Java set are identical with those still inhabiting that country, 

 an almost equally large proportion of the Australian set are 

 distinct, though often very closely allied species. It is to be 

 observed, also, that these representative or allied species di- 

 minish in number as they recede from Australia, while they 

 increase in number as they recede from Java. There are 

 two reasons for this, one being that the islands decrease rapid- 

 ly in size from Timor to Lombock, and can thei-efore support a 

 decreasing number of species ; the other and the more impor- 

 tant is, that the distance of Australia from Timor cuts off the 

 supply of fresh immigrants, and has thus allowed variation to 

 have full play ; while the vicinity of Lombock to Bali and Java 

 has allowed a continual influx of fresh individuals, which, by 

 crossing with the earlier immigrants, has checked variation. 



To simplify our view of the derivative origin of the birds 

 of these islands, let us treat them as a whole, and thus per- 

 haps render more intelligible their respective relations to Java 

 and Australia. 



The Timor group of islands contains : 



Javan birds 3G I Australian birds 13 



Closely allied species 11 Closely allied species 35 



Derived from Java 47 [Derived from Australia 48 



We have here a wonderful agreement in the number of 

 birds belonging to Australian and Javanese groups, but they 



