ZOOGEOGRAPHY. 155 



widely distributed on Sumatra. The fact that the Javan fauna came from the 

 mainland by way of Sumatra alone, and that the Timor arc would not seem to 

 have been projected to the mainland independently of Sumatra, need not in any 

 way effect a presumption that the Timor arc may have been continuous, and had 

 existence before the arc of the present Lesser Sunda chain came into being. The 

 latter may have had more recent origin by extravasation and accumulation, and 

 this may have accounted for sinking of the ancient land; and this sinking then 

 left Timor and Sandalwood the sole remannts of what was perhaps once an 

 ancient land-bridge from west Australia to the region where Java is now. 



If Timor and Sandalwood have had tliis relation to both Australia and the 

 mainland, one would expect to find on them some of what are always called the 

 "ancient Australian types." Why these types should be supposedly so very 

 ancient is not quite clear, for there would seem to be but few types now in exist- 

 ence in AustraHa which would require us to assign to them an origin much pre- 

 vious to early Tertiary times. As a matter of fact, in spite of their structure, 

 the fauna of both of these islands is strikingly similar to that of the other islands 

 of the Lesser Sunda chain, except for certain forms in Timor which are discussed 

 later. There can be no doubt that they both have been joined to this chain in 

 recent geologic time. The anomolous forms in Timor are not antique relics 

 derived from Australia, but are rather apparently of Papuasia origin. Wliether 

 the ancestors of the characteristic Austrahan forms came through Sandalwood 

 and Timor in coming from Asia, and died out there naturally ; or whether they 

 were destroyed by subsequent telluric disturbances, can never be answered. 

 They may, on the other hand, most of them have come by way of Antarctis, — 

 perhaps even have had origin there; and in this case it is not, of course, necessary 

 to presuppose that a continuous connection has ever existed between Australia 

 and the continent of Asia. 



The remarkable development of Ophidia proteroglypha in Australia can 

 hardly be explained by assuming that they came from South America. The 

 many species in Africa, and the scattered species in southern Asia, would rather 

 lead one to suppose that these were the remnants of a once more general popula- 

 tion of similar forms which have died out in extensive regions where they have 

 come into contact with the more modern and successful viperine and crotaline 

 types to which they themselves gave rise; while the proteroglyphs in Australia 

 did not happen to evolve into these competing types as they did in other regions, 

 and they themselves remained predominant, and form practically the whole 

 Australian ophidian fauna. Their origin in Asia, and their probable spread from 



