444 QUADRUMANES. 



which are stained black ; the two inner tubercles are polished flat 

 by attrition, but retain their enamel : in the upper molars the outer 

 tubercles are in the latter state, the inner half presents a deep 

 excavation of the dentine, which is stained black. 



In the great Orang-utan {Simia Wurmbii, PL 117, fig. 1 & 2) 

 the median incisors of the upper jaw are of unusual size and 

 strength ; the thickness (antero-posterior diameter) of the base of 

 the crown almost equals the breadth of the same ; and they are 

 double the size of the lateral incisors {i fig. 2). The abraded 

 surface of the front incisors in the old Orang forms a broad tract 

 extending obliquely from the cutting edge to the back part of the 

 base of the crown ; the lateral incisors are more pointed, the outer 

 angle being obliquely truncated : a vacant space of their own breadth 

 divides them from the canines. These, in the male of the great 

 (Wurmb's Pongo, c) have a long and strong slightly curved crown, 

 Orang extending below the alveolar border of the under jaw when the 

 mouth is shut, with a moderately sharp posterior margin, but 

 without an anterior groove : the crown is convex externally, with 

 a slighter convexity between two longitudinal depressions on the 

 inner surface. In the female Orang (fig. 3) the canines are 

 smaller; the crowns extend only a short distance beyond the level 

 of the adjoining molars. The male of the smaller and more an- 

 thropoid species of Bornean Orang, which I have called Simia 

 Morio, (fig. 4) has the canines less developed in proportion to 

 those of the female. (1) In both species of Orang the two cusps 

 of the first premolar are rather more produced than those of the 

 second, as is likewise the outer and anterior angle of the base of 

 the crown. The first and second true molars are rather larger than 

 the third ; they have each four cusps, but less developed, and 

 with shallower interspaces than in the Baboons and Monkeys. The 



(1) Zool. Trans, vol. ii, p. 1655, PI. 33, Oct. 1836. Mr. Brooke, the enterprising traveller 

 in Borneo, has transmitted skulls of both sexes of S, Morio to the Zoological Society, and fully 

 confirms my determination from cranial evidence of the two distinct species of that island. He 

 says, "The natives of the north-west coast of Borneo are all positive as to the existence of two 

 distinct species." " The Mias Pappan is the Simla Wurmbii of Mr. Owen, having callosities on 

 the side of the face. The Mias Kassar or Simia Morio, is the same colour as the Mias Pappan, 

 but altogether smaller and devoid of callosities either on the male or female adults." — Pro- 

 ceedings of the Zoological Society, 1841, p. 55. 



