7i8 THE HIGHER ANTHROPOIDS 



longitudinal coeflicicnts of tlic- nucleus ruber in gorilla, chimpanzee and orang- 

 outang are given in the lollowing tahuhition: 



Coefficients of the Red Nucleus in the Higher Anthropoids 



This nucleus is larger in all of the great anthropoids than it is in the 

 intermediate primates. The dilfcrencc in size becomes even more striking 

 w hen compared with the lower forms. The evidence, therefore, Ixiscd upon 

 the cerebellar nuclei and the red nucleus indicates a progressive expansion 

 which is consonant with increased coordlnative control. Such control is 

 incident to the acquisition of the complex aetiNities determined i^y the 

 development of the hand. 



VI. The Pontile Nuclei in Their Relation to the Control of Skilled 

 Movements, Especially Complex Mani al Performances 



Few elements in the nervous system allord more convincing evidence ol 

 the evolutional process than the pontile nuclei. Their status indicates the 

 degree of expansion in the cerebral cortex, particularly the neopallial portion 

 of this cortex. Contributions to the fiber constituents which reacii tlie pontile 

 nuclei are made by tiie Irontal lobe, the parietal lobe, the temporal lobe and 

 in all probability also from areas of the occipital lobe. The volume ol this 

 nuclear mass thus beconu's a reliable index of exi)ansion in thecerel)ral cortex. 

 Like the pyramidal system, the contingents of nerve fibers which comiect the 

 cortex with the pontili' nuclei are expressive of neokinetie actixities. They 

 denote the motor potentialities inherent in the mammal as well as the degree 



