144 



NATURAL HISTORT OF THE [chap. is. 



of tlie species are quite distinct, there are only about fifteen 

 peculiar genera, and not a single family group confined to 

 the former district. If, however, we compare the islands 

 with the Burmese, Siamese, and Malayan countries, we 

 sliall lind still less difference, and shall be coimnced that 

 all are closely united by the bond of a former union. In 

 such well-known families as the woodpeckers parrots, 

 trof^ons, barbels, kingfishers, pigeons, and pheasants, we 

 find some identical species spreading over all India, and 

 as far as Java and Borneo, while a veiy large proportion 

 are common to Sumatra and the JIalay peninsula. 



The force of these facts can only be appreciated when 

 we come to treat of the islands of the Austro-Miday 

 region, and show bow simUar barriers have entirely 

 prevented the passage of l>irds from one island to aiiother, 

 so that out of at least three hundred and fifty land birds 

 udmbiting Java and Borneo, not more than ten have 

 passed eastward into Celebes, Yet the Straits of Macassar 

 are not nearly so wide as the Java sea, and at least a 

 hundred species are common to Borneo and Java, 



I will now give two examples to show how a know- 

 ledge of the distribution of aiumals may reveal imgua- 

 pected facts in the past history of the earth. At the 

 eastern extremity of Sumatra, and separated from it by a 

 strait about fifteen miles wide, is the small rocky island of 

 Banca, celebrated for its tin mines. One of the Dutch re- 

 sidents there sent some collections of birds and animals 

 to Leydcn, and among them were found several species 

 ilistinct from those of the adjacent coast of Sumatra One 

 uf these was a squirrel (Sciurus bangkanus), closely allied 

 to three other species inhabiting respectively the Malay 

 peninsula, Sumatm, and Borneo, but quite as distinct from 

 them all as they are from each otlier. There were also two 

 new ground thrushes of the genus Pitta, closely allied 

 to, but ([uite distinct from, two other species inliabiting 

 both Suuiatni and Borneo, and which did not perceptibly 

 differ in these large and widely separated islands. This is 

 just as if the Isle of Man possessed a peculiar species of 

 thrush and blackbird, distinct from the birds which are 

 common to England and Ireland. 



These curious facts would indicate that Banca may heve 



