184 PON GO 



the native hunters. And in this he would be fully justified, for those 

 of us who have had experience with native collectors in savage lands, 

 know perfectly well that the localities they give their specimens 

 cannot often be relied upon. However this may be, these Ourang skulls 

 are without any particular locality, but simply have marked on them 

 a letter to indicate the district from which each one supposedly came. 

 Thus 5. stands for Skalau District ; B. for Batangtu ; D. for Dadapai ; 

 G. for Genepai ; L. for Landak ; R. for Rantau ; and some half dozen 

 were found, all very young skulls, to represent the races he called 

 tuakensis, obongensis, and wallacei. Another fact in regard to these 

 skulls, was the infinite variations they exhibited. No two in the 280 

 were alike, and even some from the same locality, or at all events the 

 same district, varied to an amazing degree. A study of this material 

 proved that an attempt to establish species upon cranial characters 

 would be futile, and it may be for that reason Herr Selenka did not 

 attempt it, but endeavored to found his species upon the cubical di- 

 mensions of the interior of the braincase, about as hopeless a pro- 

 ceeding, as to try to subject the endless variations of the rest of 

 the crania to some degree of uniformity. This was the only material 

 available for the determination of species, and other interesting points 

 connected with the Ourang-utan. A large series of crania, the largest 

 in existence, mostly those of very young animals, and females, only 

 a few of the latter being adult, and some old adult males, (of these 

 last I was able to select eighteen out of the lot), none of which had 

 a particular locality given to it, and no skins for any of them. The 

 outlook was far from encouraging, but the material was the best in 

 existence, lamentably defective as it was in most important points. 

 Nothing could be done towards the solution as to the cause of the 

 presence or absence of callosities, and although we knew from Selenka's 

 statements, that individuals with and without callosities were obtained 

 in the same districts, the skulls gave no sign as to whether they had 

 been present or not. 



Herr Selenka bases his species mainly upon the cubical dimensions 

 of the interior of the braincase, and upon certain theories, for much 

 of which he has produced no proofs. According to his own tables, 

 cubical dimensions are very unsatisfactory characters, for rarely do 

 two crania agree in their dimensions, and we must regard this method 

 as one quite unsuitable per se, for the determination of the species. 

 His theory is as follows: Borneo is intersected by wide and deep 

 rivers, and since Ourangs can neither swim rivers, nor climb moun- 

 tains, they are hemmed in on sections of land as if on islands, and 



