150 BARBOUR: ZOOGEOGRAPHY. 



address before the Seventh international zoological congress on The evolution of 

 continents as illustrated by the geographical distribution of existing animals 

 (Proc. 7th intern, zool. congr., 1907, 1909, separate, p. 10-11, 1912, p. 864-865), 

 wrote : — 



"Within recent years, it has been shown that Australia must have been 

 joined to Asia by land. This land-bridge existed, no doubt, in rather remote 

 times, probably towards the close of the Secondary era, and became broken up 

 perhaps during the eocene period. 



"Wallace acknowledged that the Asiatic mainland extended as far to the 

 southeast as Borneo within comparatively recent times, and that a large tract 

 of country had since sunk, so as to produce the present configuration of the Indo- 

 Malayan region. He was particularly impressed by the apparent sharp line 

 of demarcation in the faunas between the small islands of Bali and Lombok, and 

 assumed that the latter were separated by a marine channel of great depth. 

 It has been now clearly established, however, by Weber, that no such deep 

 channel intervenes between these islands, and that their faunas are by no means 

 so distinct as Wallace supposed. 



"The faunistic relationship of the numerous islands of the great Indo- 

 Australian archipelago and their geological history is being energetically worked 

 out at present with the aid of the geographical distribution of animals. 



"Since Wallace's classic investigations in this archipelago, foremost in im- 

 portance from our point of view are the researches of the two Sarasins. Their 

 remarkable work on the geological history of the island of Celebes, based on 

 animal distribution, may truly serve as a model to those prepared to devote 

 themselves to pursuits of a similar nature. From the time, in the dawn of the 

 Tertiary era, when the island was still submerged by the sea, they trace its 

 gradual evolution, the geological history of its immigrants, and its final separation 

 from other land masses. They show that though Celebes was connected with 

 Australia by way of New Guinea, westward with Java, Sumatra and the Malay 

 peninsula, and also northward with the Philippine Islands, the Strait of Macassar 

 always separated it directly from Borneo." 



Again, later still, van Kampen, in a paper entitled "De zoogeografie van 

 den Indischen Archipel" (Nat. tijdschr. Ned. Ind., 1909, separate, p. 1-24) 

 has given us an excellent historical account of East Indian zoogeography. An 

 English translation of this paper will be found in the American naturalist, 

 1911, 45, p. 537-560. It seems hardly worth while to repeat here a discus- 

 sion of the work of Miiller, Earle, Wallace, the Sarasins, Max Weber, Pelseneer, 



