CHAP. Vl] THE DENTAL SYSTEM OF THE PRIMATES 



253 



ANTHROPOIDEA. Simiidae. Hylobates (miilleri). Fig. 184. 



The incisor teeth have the general characters of those of Oercopithecidae. 

 It is to be noticed as a difference (cf. Fig. 183 with Fig. 184) that in Hylobates 

 the crown is much less extensive in the vertical direction, both absolutely 

 and relatively. The comparative smallness of the crown is seen again in the 

 Orang-utan. 



ANTHROPOIDEA. Stmiidae. Simia satyrus (Orang-utan). Fig. 185. 



The median upper incisors far surpass the lateral incisor teeth in size : the 

 small size of the upper crowns is very remarkable. Of the lower teeth the 

 median pair exceed the lateral pair in bulk usually but not always. 



Fig. 185. Fig. 186. 



Fig. 185. Incisor teeth of an Orang-utan (ad. <? W. L. H. D. priv. coll.). 

 Fig. 186. Incisor teeth of a Gorilla (ad. <f W. L. H. D. priv. coll.). 



ANTHROPOIDEA. Simiidae. Gorilla savagii. Fig. 186. 



The difference in the sizes of the median and lateral upper incisor teeth is 

 less marked in the Gorilla, but the median pair are still the larger. In the 

 lower series the opposite proportion obtains. The upper crowns are more 

 extensive than in Hylobates and Simia, and recall the type found in Oerco- 

 pithecidae. 



ANTHROPOIDEA. Simiidae. Anthropopithecus niger. Fig. 187. 



The upper median teeth are larger than the upper lateral teeth; the 

 crowns are extensive (as in Gorilla) ; of the lower teeth, the median and lateral 

 pair are nearly equal in bulk. It is very noteworthy that in the Chimpanzees, 

 the incisor teeth may often equal or even surpass in bulk the incisor teeth of 

 the male Gorilla, while the molar teeth and indeed the whole skull of the 

 ( ihimpanzee are much smaller than that of the male Gorilla. 



