164 BARBOUR: ZOOGEOGRAPHY. 



Morotai, and Obi will follow in the order named, which is the sequence in which 

 their comparative areas place them. 



The competition to which the different individuals of a species are subjected 

 is probably of a completely different sort from that between different species; 

 the latter sort of competition, a phenomenon of which we know little or nothing, 

 is probably the real cause for the relation which area bears to species population. 



A glance at the table of distribution, p. 169-203, will show at once that, so 

 far as the distribution of ReptiUa and Amphibia is concerned, there is no evidence 

 whate^•er of the existence of what has been called a Wallace's line, a Weber's line, 

 or any other similar faunistic boundary. To be sure, a few conspicuous forms 

 might be chosen whose limits of distribution more or less coincided, and to this 

 limit a "Line name" might be given. Such lines could be drawn anywhere 

 through the whole area, and each would limit the distribution of some form or 

 forms. Probably no species reaches from Malaya to Papua unchanged. Di- 

 hamus novae-guineae is supposed to do this now, but the identification upon 

 which the Malay Peninsula records rest was perforce based upon the stud}^ of an 

 immature example. A number of Malayan species do reach Halmahera, Mysol, 

 Ceram, the Ke Islands, and Timor-Laut; and this north-south series of islands 

 forms the only semblance of a zoologlc frontier in the region. Moluccan species 

 of Malayan genera have reached Papua in numbers, and many other Malaj-an 

 genera are represented in Papua by pecuUar species. Papuan species are trace- 

 able to Celebes and Lombok. Here again that this gap is bridged is shown by 

 the number of species which are common to Sumatra, Java, and Celebes, or to 

 Sumatra, Java, and the Lesser Sunda chain. Thus, no line of demarcation 

 having a fundamental significance is reallj' existent here. 



An intensive study of Ceram, Burn, the Sula Islands, and some of the 

 Lesser Sunda Islands, both between Timor and Timor-Laut, and between Timor 

 and Java, will be necessary before the subject can be really satisfactorily attacked. 

 The work of the Sarasins in Celebes, and of Kiikenthal in Halmahera, stand out 

 as superb examples of what can be done; but more, far more, such work is needed. 



I have tried in this paper to collect all the existing authentic data regarding 

 the occurrence of Reptilia and Amphibia in the Ai'chipelago, as well as to define 

 their distribution, and, so far as possible, point out the probable origin of the 

 herpetologic fauna of each island. The task has been aided by a knowledge of 

 geographic conditions which only a voyage through the Archipelago can give; 

 nevertheless no one can realize more fully than I how inadequate has been my 

 treatment of a most absorbing subject. 



