474 Mr. A. R. Wallace on the Orang-Utan or Mias of Borneo. 



which I obtained were respectively 3 ft. 8^ in. and 3 ft. 9| in. 

 in height, 6 ft. 6 in. in extent of arms, and about 2 ft. 6 in. in 

 girth of body. They possessed no signs of the cheek-excres- 

 cences, but in other respects resembled the larger kinds. The 

 skull is smaller and weaker, and the zygomatic arches narrower 

 than in the large species ; it has no bony crest, but two faint 

 ridges from IJ inch to 2 inches apart, exactly as in the Simla 

 Morio of Prof. Owen, figured in the ' Transactions of the Zoolo- 

 gical Society.' The teeth however are in proportion to the skull, 

 of immense size, equalling, and in one case surpassing, those of 

 the larger animals : the molars extending further backward, and 

 the incisors and canines being set closely together, room is 

 found for them in a much smaller jaw. The great canine teeth 

 are quite as large as in most specimens of the larger animal, 

 and of exactly the same form. These animals the Dyaks called 

 " Mias Kassu.'^ 



The adult females, five in number, examined by me exhibit a 

 remarkable uniformity among themselves, and a striking differ- 

 ence compared with the large males. In size they vary only from 

 3 ft. 6 in. to 3 ft. 7 in. in height, from 2 ft. 4 in. to 2 ft. ^ in. 

 in girth below the arms, and from 5 ft. 9 in. to 6 ft. 5|^ in. in 

 extent of arms. None possess any cheek-excrescences, some 

 have and some want the nail on the great toe, the colour varies 

 considerably, but the external characters are in general remark- 

 ably similar to those of the smaller males before mentioned, 

 from which they only differ in a stature from \^ in. to 3 inches 

 lower. Their crania are either equal to or slightly less than 

 those of the small males ; but their teeth differ remarkably from 

 those of all the males, in the canines being comparatively small, 

 and of the peculiar subtruncated form, dilated at the base, which 

 is represented in the plate of Simia Morio before alluded to. 

 With that plate most of these crania exactly agree ; I presume 

 therefore that it represents a female specimen, and that the 

 peculiar form of canine tooth is characteristic of the female sex. 

 The question then remains, to which of the two forms of male 

 animal are these the females. From a careful examination 

 of my specimens I am induced to consider that most of 

 those, the crania of which equal in size those of the small 

 males, may be referred to the larger species, while one or two, 

 slightly smaller in all their dimensions, but remarkable for 

 having the two middle incisors in the upper jaw larger than in 

 the other specimens, may be considered as the females of the 

 smaller species, the male of which has also those teeth larger 

 than in the animals which possess huge crested skulls and cheek- 

 excrescences. These smaller females so exactly correspond with 

 Prof. Owen's figure, that there is no doubt of their belonging to 



