PONGO 185 
thereby prevented from mingling with their kind in other portions 
of Borneo. Let us consider this idea a moment and see if it is 
sufficiently correct and forcible to merit acceptance. As far as 
Europeans have ascended the rivers of Borneo, it is, I believe, a fact, 
that Ourangs have been seen in the forests along the banks, but there 
is no proof that they may not be dispersed throughout the forests 
far into the interior, the conditions being the same. It is probably 
quite correct to say that Ourangs cannot swim wide and deep rivers 
near their mouths, but higher up, where the width is less, and the 
water shallow, and where the trees possibly overarch the stream, 
Ourangs can cross and join their fellows on the opposite side. It is 
not unreasonable to suppose that they often do this, and in the dry 
season it is probable that the rivers are very low, and some possibly 
almost dry. Then the objection that they cannot climb mountains, 
and that these would prove an insurmountable barrier in their path. 
This is a curious statement coming from one who has described a 
species or race as new, living upon a mountain and in its vicinity, dadap- 
pensis! But we know, on the testimony of Wallace, given farther on, 
that Ourangs can, and do, climb mountains. It is probably a fact 
that if a steep mountain is bare of trees the Ourang could not ascend 
it, and very likely would not try, but if it were covered with forests 
the animal would find no difficulty in reaching the top, and Borneo is a 
forest covered island with possibly only a few of the highest peaks 
bare of trees. Wallace, moreover, states the fact, that in the Sadong 
Valley District, there are many isolated mountains which the Dyaks 
have covered with fruit trees, and the Ourangs ascend these to feed 
on the unripe fruits, retiring to the low swamps at night. It will thus 
be seen that both Herr Selenka’s method and theories for establishing 
his species are subject to grave objections, and are not sufficiently 
satisfactory in the one case, nor probable in the other, to merit 
general acceptance. 
Now for consideration of the species described by him. And 
first there are no types; that is to say, Herr Selenka did not select 
any particular specimen as THE representative of a species. With 
the Ourangs, however, this is not of supreme importance so far as 
the skulls are concerned, because, if Selenka had selected any particular 
one for his type, it would be found not to agree in its characters with 
any other, so infinite are the individual variations of the crania in a 
large series of examples. All the skulls therefore from a certain 
district must be taken for consideration, as representing a type with 
all its variations, and exhibiting the general characteristics of the 
