186 PON GO 



form found in that particular section of Borneo. It must be borne in 

 mind, however, that the part of Borneo from which Herr Selenka 

 obtained his material is a very limited area of the island, entirely too 

 small to possess any considerable number of species of Ourangs, 

 especially as it is well covered with forests through which the Apes 

 could travel as they chose, and there are no ranges of lofty mountains 

 to act as barriers to their progress. Yet in this comparatively small 

 district he describes seven races as distinct, viz. : P. s. landakensis, P. 

 s. batangtuensis, P. s. dadappensis, P. s. genepaiensis. P. s. skalauensis, 

 P. s. tuakensis, and P. s. rantaiensis. Of these batangtuensis was 

 supposedly previously described, and the remainder are all antedated 

 by PoNGO PYGM^us Hoppius for the reasons hereafter given. After 

 a careful examination of these skulls, (no skins being available), and 

 witnessing the almost incredible variations exhibited, and which are 

 not confined to any locality, skulls from the same place differing as 

 greatly from each other as they do from those in another district, and 

 finding no character common to all of them, or even to a few of them, 

 which can be regarded as indicating specific distinction, I was forced 

 to the conclusion that these variations are simply individual, and may 

 not in any degree be regarded as indicating a specific value. I could 

 find nothing in this large series of crania which would distinguish 

 those of one district, as a whole, from those of any other, and if a 

 cranium from one locality exhibited some marked difference from 

 others from another place, it would be found that its mate from the 

 same district would not agree with it in this particular point. Failing 

 therefore to discover any cranial character by which any kind of 

 distinction could be established, I was obliged to conclude that but 

 one species of Ourang was represented in this collection from Borneo. 

 With regard to the cheek callosities, found only on old adtilt 

 males, I do not believe these indicate a specific character, or are even 

 dimorphic, as the Hon. Walter Rothschild has considered them to be 

 in his paper. It has been proved that Ourangs with and without 

 callosities are found in the same district, Selenka so states, and material 

 otherwise received from Borneo confirms the fact. It is not to be 

 believed that two distinct forms inhabit the same range of country 

 characterized only by the presence or absence of these peculiar for- 

 mations. It is not reasonable to think so. Then callosities are confined 

 to some old males only, and among these, such growths vary greatly 

 in size. The skulls, as I have said, give no indication either of the 

 presence or absence of these callosities, and if one had to depend 

 upon them alone, he would be totally unable to know in which group 



