7i6 THE HIGHER ANTPIROPOIDS 



a (k'diiitt' Linfolcling which gains siibstaiiliation from the fact tliat actual 

 expansions arc taknig place in the hitcral cerebellar lobes. The dentate 

 nucleus ni the orang-outanij; shows a relativclx low degree of dillerentiation 

 in so far as its boundaries are concerned. It has a diffuse uncircumscribcd 

 appearaiH'c w hieh relates it niuch more closel\- to the corresponding structure 

 ni the niterinediate and lower pruiiatcs than it does to those forms standing 

 abox'c It 111 the scale. The degree ot coiuolution in the dentate nucleus is 

 consick'rablv inlenor to that oi man, chimpanzee or gorilla. In comparing the 

 nucleus ol tlu' higher primates it appears at once that the orang is the most 

 primitixe in morphological organization. This inlerioritx of the dentate 

 nucleus m the orang corresponds w ith the conditions in the lateral lobes w hich 

 have not expanded to the extent seen in the primates assigned to higher posi- 

 tions in this order. The dentate nucleus in the chimpanzee is much more 

 clearly delmed than in the orang and has a richer coiuolutional pattern. On 

 the other hand, there is a primit neness about its festooning and foliation 

 whicii easil\ distinguishes it from t lu' corresponding structure in the human 

 and gorilla brains. If the dentate nuck'us in man be accepted as the standard 

 towaicl which the (.■volutional process has been tending, it seems reasonable 

 to assign to the gorilla a position immediately below the human t\ pe and 

 distinctly above the chimpanzee. This lact in coiiiunction with the high 

 degree o I dexelopnient m the latt'ral IoIjcs ol the ccrcbi'llum implit's that the 

 gorilla stands lirst m the group ol the great anthropoids in so far as the coor- 

 dmatiNH' control ot its muscles is concerned. 



COMl'AHISON OF THE GREAT ANTHROPOIDS AND THE INTERMEDIATE PRIMATES 



When compared with the intermediate primates the great anthropoids 

 show no great adxantage demonstrated b\ mensuration of the (K'litate 

 nucleus. On the other hand, in morphological particulars it is e\ ideiit that a 



