332 MAMMALIA. 



Order 14. PRIMATES ., PITHECI* (APES). 



With complete dentition and chisel-shaped incisors in closed series 



J 



on each side ; usually with prehensile feet on the hind limbs, and as a 

 rule, with hands on the front limbs ; with closed orbit and two pectoral 

 mammae. 



The Apes, as a rule, are of slender build, corresponding with their 

 quick and easy movements as arboreal animals ; there are, however, 

 heavy unwieldy forms, which, as the Baboons (Cynocephalidce), avoid 

 forests and inhabit rocky mountain regions. The body is more or 

 less closely covered with hairs, except on the face, which is naked in 

 parts, and the callous parts of the buttocks (ischial callosities). The 

 hair is often longer in places on the head and trunk, forming tufts 

 and manes. The human look of the face depends mainly upon the 

 slight prominence of the jaws, and is greatest in the early part of 

 life. The facial angle of the adults rarely exceeds 30 ; but in one 

 case, viz., in Chrysothrix sciurea, is almost twice that size. With the 

 increase in size of the brain, the cranial capsule becomes rounder, and 

 the foramen magnum gradually moves from the posterior part on to 

 the lower surface. The pinna of the ear also has a human look, as 

 has also the position of the anteriorly directed eyes. The orbits are 

 completely closed towards the temporal fossae. Further, the mammae 

 are two in number and pectoral in position, as in Man. Finally, the 

 dentition and the structure of the extremities (fig. 703) are so 

 similar to those of Man, that he has been placed in the same order 

 as the Apes. There are in each jaw four chisel-shaped incisors, 

 which, as in Man, are placed close to one another without any 

 interval. There are projecting conical canines, and in the Apes of the 

 Old World five, in those of the New World six bluntly-tuberculated 

 grinders, the form of which indicates that the diet is mainly vege- 

 table. The size of the canines, which project almost as much as 

 those of the Carnivora, occasions the presence of a considerable gap 

 between the canines and the first prsemolars of the lower jaw. 



The anterior limbs are usually longer than the posterior. A 

 clavicle is always present. The forearm permits of a rotation of 

 the radius round the ulna, and accordingly of the pronation and 

 supination of the hand, the fingers of which, except in the 



* Vrolik. " Becherches d'anatomie comp. sur le Chimpanze," Amsterdam, 1841. 



G. L. Duvernoy, ' ; Des caracteres anatomiques des grands Singes pseudo- 

 anthropomorphes," Arch, du Museum, Tom. VIII., 1855. 



K. Owen, " Osteoloey of the Anthroponiorphidse,'' Transact. Zool. Soc,, vol. i, 

 1835 ; vol. ii., 1841 ; vol. iii., 1849 ; vol. iv., 1853. 



