THE CHIMPANZEES AND ORANGS. 175 
energy and consequent activity. Those males which are so endowed will acquire, 
by the more frequent and energetic exercise of their biting muscles in such conflicts, a 
greater development of these muscles ; just as the blacksmith or boxer gains a greater 
bulk and firmer fibre in the muscles of the arms; and, as this development of the 
brachial muscles is indicated by stronger ridges on the humerus, so the corresponding 
development of the biting and fighting muscles in the combative Orangs is accompanied 
by the confluence of the temporal ridges and their development into an intermuscular 
crest along the top of the calvarium. 
Males of a more peaceful and sluggish disposition have not the stimulus for the extra- 
development of the temporal muscles, the upper borders of which accordingly remain 
at a greater or less distance from each other, and the temporal ridges are more or less 
apart. ; 
No physiologist would interpret such modifications in the development of a particular 
pair of muscles as a specific distinction. The question, with me, in 1836, was, whether 
intermuscular crests or ridges, with other observed varieties, in the skulls of the large 
Orangs of Borneo and Sumatra, were constant in particular breeds, or were indicative 
of local varieties. The number of skulls, however, of ascertained Bornean origin has, 
for some time past, satisfied me that there were no ascertained craniological characters 
differentiating the great Bornean Orang from the great Sumatran one. The valuable 
and acceptable evidence lately adduced by Mr. Wallace’, proves that the single-crested 
and double-crested, or non-crested, skulls of the great males are not respectively the 
indications of races inhabiting any particular localities in Borneo, but occur in indi- 
viduals resembling each other in stature, in kind and colour of hair, and in cheek-pro- 
tuberances: such individuals have been shot in the same limited tract of country. 
The skull of the crested variety of the male great Orang (Pithecus Satyrus) is figured 
by Mr. Blyth, as the Mias Pappan, in plates 1 and 2 of his ‘‘ Remarks on the different 
Species of Orang-utan.” The skull of the non-crested or double-ridged variety of the 
male great Orang is figured, as the Mias Rambi, in plates 5 and 6 of the same memoir. 
Plates 3 and 4 are stated to be of an aged female of the Mias Rambi, from Borneo. 
This specimen is referred to, at p. 1 of Mr. Blyth’s memoir, as “‘ an aged female skull 
marked ‘from Borneo’ in this Society’s Museum,” and again at p. 8, as ‘“‘an aged 
female skull of a Mias Rambi from Borneo.” I have looked closely through every part 
of Mr. Blyth’s ‘“‘ Remarks,” in the hope of finding some direct evidence of the sex of 
this specimen. It would seem that the sole record received with the specimen related to 
its locality. The size of the canines, in the plates of Mr. Blyth’s memoir, satisfies 
me that the specimen was of the male sex. The degree of abrasion of these teeth, 
of the incisors, and of the outer portions of the inferior molars, indicates it not to have 
been very old. It exemplifies the single-ridged variety of cranium, of the adult male 
Pithecus Satyrus. 
2 
1 Loc. cit. p. 472. 
2c2 
