SUiMMAin' 01- ^TRICTL'RFS 



715 



primatfs, ihc Ncslihular complrx, althouuh it indicates the gciuTal conserva- 

 tism inlKTent in the eciuih'hratory elements of motor organization, reveals a 

 marked susce])tibihty e\ en on x\\c jjart ol'such archaic structures to inlhienccs 

 developed I)y the irresistible sj^ecializing factors of adapti\ e modification. 



V. The Cerebellar Nuclei and Red Nucleus in Relation to the 

 Coordination of Mo\ ements, EsPECIALL^■ the More Complex 



jMo\ E-MENTS OF 1HE UpPER ExTHENH I V 



In the matter ol coordinati\e control of the musculature, dillerences in 

 the ec[uipment of the great anthropoids are not marked. W hatever slight 

 planimetric advantage may exist is in faxor of the orang-outang, although 

 the gorilla is close behind it in this sjjccialization. While the basis for 

 this contrast is allorded b\ the size partlcularix ol the dentate nucleus, 

 it also includes the conliguratioii of the structure. The coellicients of 

 the dentate nucleus in the three great anthropoids are given in the follow- 

 ing tabulation : 



IMI'OKIANCE Ol-^ MORPHOLOGICAL APPEARANCES 



Conclusions based \vholl\- upon these ligures do not give a comprehen- 

 sive view of the actual dilferentiat ion in this part of the central nt'r\-oiis 

 system. Quite as importantas the mensurationof the nuclei is their morpholog- 

 ical appearance. In two features of the dentate nucleus it is possible to trace 



