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 

 difiierentiating 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 difterent 

 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 frism 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. 



' Loc. cit. p. 472. 



2 c2 



