1863.] BIRDS OF TIMOR, FLORES, AND LOMBOCK. 483 



nected with Java by a chain of broken land divided by straits which 

 are nowhere more than about twenty miles wide. Evidently there 

 are now great facilities for the natural productions of Java to spread 

 over and occupy the whole of these islands, while those of Austraha 

 would find very great difficulty in getting across. To account for 

 the present state of things, we should naturally suppose that Aus- 

 tralia was once much more closely connected with Timor than it is 

 at present ; and that this was the case is rendered highly probable by 

 the fact of a submarine bank extending along all the north and west 

 coast of Australia, and at one place approaching within twenty miles 

 of the coast of Timor. This indicates a recent subsidence of North 

 Australia, which probably once extended as far as the edge of this 

 bank. I do not think Timor was ever absolutely connected with 

 Australia, because the representation of the forms of that country 

 is not sufficiently perfect. There are no Kangaroos in Timor, nor 

 indeed any Marsupials whatever, except a Cuscus, which is a Moluc- 

 can and not an Australian genus. Many highly characteristic genera 

 of birds are also absent which we should certainly expect to find 

 had the countries ever been connected, such as Calyptorhynchus, 

 Malurus, Cracticus, Anthochcera, Po'ephila, Falcunculus, Colluri- 

 cincla, &c. Nor do any of the characteristic Australian groups of 

 insects occur in Timor. Everything indicates therefore that a strait 

 of the sea has always separated it from Australia — a supposition 

 which is confirmed by the deep gulf that still runs between its rocky 

 southern coast and the edge of the before-mentioned submarine bank. 

 But at the time when this narrowing of the sea took place in one 

 direction, there must have been a greater separation at the other end 

 of the chain, or we should find more equality in the numbers of 

 identical and representative species derived from each extremity. It 

 is true that the widening of the strait at the Australian end by sub- 

 sidence would, by putting a stop to immigration and intercrossing 

 of individuals from the mother country, have allowed the full action 

 of the causes which have led to the modification of the species ; 

 while the continued stream of immigrants from Java would by con- 

 tinual intercrossing check such modification. This view will not, 

 however, explain all the facts ; for the character of the fauna of the 

 Timorese group is indicated as well by the forms which are absent 

 from it as by those which it contains, and is by this kind of evidence 

 shown to be much more Australian than Indian. No less than 

 twenty-nine genera, all more or less abundant in Java, and most of 

 which range over a wide area, are quite absent ; while of the equally 

 diffused Australian genera only about fourteen are wanting. This 

 would clearly indicate that there has been till recently a wide sepa- 

 ration from Java ; and the fact that the islands of Baly and Lom- 

 bock are small and are almost wholly volcanic, and contain a smaller 

 number of modified forms than the other islands, would point them 

 out as of comparatively recent origin. Here probably existed a wide 

 arm of the sea at the time when Timor was in the closest proximity 

 to Australia ; and as the subterranean fires were slowly piling up 

 the now fertUe islands of Bali and Lombock, the northern shores of 



