720 THE HIGHER ANTHROI^OIDS 



Coefficients of the Pontile Nuclei in the Higher Anthropoids 



CO.MPAKISOX OF THE PONTILE ELEMENTS OF THE GREAT APES WITH THE 

 INTERMEDIATE AND LOWER PRIMATES 



W h;itc\cT small clillerences ma\' he apparent from these figures, tlic 

 pontile elements (jain added signKieanee when compared with those of the 

 intermediate primates. In this contrast the degree of pontile expansion 

 becomes striking. Concernmg the actual neokinetic acces'sions of the great 

 anthropoids o\ er and above their simian associates in the intermediate 

 group, there can be no room for question. The de\elopments in this depart- 

 ment ol bihaxior arc readily recognized. Such contrast ise\c'n more emphatic 

 when the pontile nuclei of the great anthropoids are compared with those 

 ol the lower [primates. A superllcial sur\e\ of these structures in the two 

 groups is sulliclent to disclose pronounced dillerenees betwx'cn tlu'in. Upon 

 actual measurement these ditferences become conxincing and the value of 

 the pontile nuclei as e\idenced b\ tlu'ir progressixc expansion stands as one 

 oi the incontestable indices concerning the process of exoUitional unfolding 

 in the brain. 



\ii. TiiF. Midbrain Collicili in Their Relation to the 

 EuNCTioNS of Sight and Hearing 



Among the higher anthropoids tin- dillerenees in the promineiux' of the 

 inferior colliculus are relatixely slight. These structures m the orang and 

 chimpanzee are essentially ec|ual; whik' iu the gorilla the interior colliculus 

 shows some tendeiu\\- to further dellorescenct'. I nterpii'ted in the light of 



