308 MALACCA — ^SUMATRA chap. 



This want of individuality in the land Mollusca.of the Malay 

 islands is accounted for by a consideration of the sea depths 

 which separate them from the Asiatic mainland. The accom- 

 panying map, the red line on which is intended to show what 

 would be the result of an elevation of the sea bottom for no 

 greater amount than 100 fathoms, exhibits clearly the fact that 

 these islands are practically a part of Asia, a large stretch of very 

 shallow sea extending between Siam and the greater part of the 

 north-west coast of Borneo. 



In all probability the three great islands of Sumatra, Java, 

 and Borneo were united with the mainland of Asia, and 

 with one another, at a period, geologically speaking, com- 

 paratively recent. This follows from the general uniformity of 

 their land Mollusca, both as regards one another and as regards 

 the mainland. Nor do the smaller mem- 

 liers of the island series — Bali, Lombok, 

 Sumbawa, Flores, Timor, and Timor Laut — ■ 

 ,^how any marked individuality in the 

 possession of peculiar genera. Wallace's 

 line is absolutely non-existent, so far as 

 the land Mollusca are concerned. The 

 Fig. 2()1.--ArioiiiiaMa Rum. ^.^.^j noticeable break in distribution 



2)hii, V. a. B., Java. -^ 



comes with the Aru Is., for while the 

 Tenimber group (Timor Laut, etc.) are decidedly Malay, and the 

 Ke Is., in the poverty of our information, uncertain, the Arii Is. 

 are as Papuan as New Guinea itself. The profound depths of the 

 Banda Sea to the north, and the Timor Sea to the south, appear 

 to have kept the islands from Flores to Timor Laut free from the 

 intrusion of any Moluccan or any considerable Australian element. 

 The Moluccas, as has been already remarked, besides possessing 

 considerable peculiarities of their own, unite a mixture of the 

 Malay and Papuan elements, and serve as a sort of debatable 

 ground for the meeting of the two. 



The Malay peninsula is practically another island of some- 

 what the same shape and general trend as Sumatra, and about 

 one-half the size. Its general relations — and the remark applies 

 to the great Sunda Islands as well — appear to be rather more 

 with Burmah, Tenasserim, and even the Cingalese district, than 

 with Siam. Points of connexion between Ceylon and Sumatra, 

 and Ceylon and Borneo, have already (p. o04) been brought out. 



