OUR BODILY FRAME. 35 



ape is much larger, and the grey bed especially, the 

 organ of higher psychic activity, is much more 

 developed ; the characteristic convolutions and furrows 

 appear on its surface exactly in proportion as the ape 

 approaches to man. In these and other important 

 respects, particularly in the construction of the face 

 and the hands, man presents all the anatomical marks 

 of a true ape. 



The extensive order of apes was divided by Geoffroi, 

 in 1812, into two sub-orders, which are still universally 

 accepted in systematic zoology — New World and Old 

 World monkeys, according to the hemisphere they 

 respectively inhabit. The American " New World " 

 monkeys are called Platyrrhince (flat-nosed) ; their 

 nose is flat, and the nostrils divergent, with a broad 

 partition. The " Old World " monkeys, on the contrary, 

 are called collectively Catarrhince (narrow-nosed) ; 

 their nostrils point downwards, like man's, and the 

 dividing cartilage is narrow. A further difference 

 between the two groups is that the tympanum is 

 superficial in the platyrrhince, but lies deeper, inside 

 the petrous bone, in the catarrhince ; in the latter a 

 long and narrow bony passage has been formed, while 

 in the former it is still short and wide, or even alto- 

 gether wanting. Finally, we have a much more 

 important and decisive difference between the two 

 groups in the circumstance that all the Old World 

 monkeys have the same teeth as man — i.e., twenty 

 deciduous and thirty-two permanent teeth (two incisors, 

 one canine, two premolars, and three molars in each 

 half of the jaw). The New World monkeys, on the 

 other hand, have an additional premolar in each half- 

 jaw, or thirty-six teeth altogether. The fact that these 

 anatomical differences of the two simian groups are 



