SUMMARY OF STRUCTURES 719 



of complexity with which the species is capable of applying its new cflcctor 

 equipment. 



The extension ol neokinetic [jossibihties in the hi}:;her anthropoids is 

 consicIeral:)le if jiKlgecl by tht' pei tormances ol these animals m captivity. 

 It was thought at one time, \\ hen the discovery ol the extinct Pak'o|)Jthecus 

 was made, that this rt-|)resentati\ c- ol the great apes had sullicii'iit intelli- 

 gence to make use ol Hints. This supposition was probably inaccurate, at 

 least in so lar as its im|)lieation suggested the purijoselul em|)lo\ment of 

 implements. On the other hand, there are man\- reliable records to show that 

 both the chimjxinzee and the gorilla do make use ol implements. In a crude, 

 inellcctual way, they actually construct accessory means lor accomplishing 

 their purposes. The manner in which the chimpanzee learns to manipulate 

 and throw stones as otleusive missiles, its use of sticks and bars lor thrusting 

 and striking are examples of thi' point in question. Furthermore the state- 

 ment that the gorilla, John Daniel, so well understood the use of hammer and 

 chisel that these tools must needs be under concealment to protect the 

 turniture, are all indications ol the degree to w hich skilled motor perlormanccs 

 may be dcxeloped in the great anthrojjoids. To (ind this development accom- 

 panied by a corresponding expansion in the pontile nuclei is not surjjrising. 

 That the gorilla, on the basis of mcasuri'ment, should apjjcar to be most 

 favored in this regard seems to have no convincing demonstration in the 

 com]:)arati\ e behaxior ot these animals. The chimpanzee is but little less 

 highly specialized in its skilled motor acts than the gorilla, while both of these 

 species excel the orang-outang, further opportunity for study of the higher 

 anthropoids may justiix the im[)ressi<)ns conveyed by the comparative 

 measurements of the pontile nuclei and actually accredit the gorilla with 

 sui)eriorit\- in its acc|uired motor performances. The planimetrie and longi- 

 tudinal coefficients of the pontile nuclei in gorilla, chimpanzee and orang 

 are gix't'ii in the folhiwing tabulation: 



