SUM \1 A in 01" STRUCTURES 717 



great adxaiHx' has Ih'imi madr in the {Iriitatc organization ol tlu' orang, thini- 

 [janzec and gorilla as coniparcd w itii tlu' intiTinccliate gronp. On the basis of 

 mcasurt'iiicnts, the baboon has a slight ad\antagc over all the great 

 anthropoids. 



COMPARISON OF THE GREAT ANTHROPOIDS AND IHF LOW I£R PRIMATES 



\\ lu-n eomparison is mack' with the lowc'r primates, all of these larger 

 apes show a distinet advaiux' both in nu'asiirement and in eonlignration ol 

 the dentatt' nueleiis. The Ijaboon is distinet l\ mierior to tlu' great anthro- 

 poids in the morphologieal details ol its dentate strLietiire. This portion 

 ol the eerebelhim whieh ser\-es as an index ol eoordinati\e eontrol alVords a 

 basis for estmiating the degree to which the extrt'mities haxf been dilleriMi- 

 tiated. it s lion Id not be ox'er looked that m all |jri mates with tin' exception ol 

 man the various species are ec|uip|)ed w ith hand-like leet. Their c|uadrumanal 

 characteristics play an important role in hiNoring the dillerentiation of hand- 

 like C|ualities. B\ dillusing these c|ualitit's through all four extremities, 

 however, they rc'tard the more deeisixe specialization which eoncentrates 

 manual dilKrent lation in the upper extremities. Upon the basis of mensura- 

 tion the intermediate primates and the great anthropoids ap|)ear to bi' on 

 about the .--aiiu' plaiu', so lar as manual dillerentiation is concerned. The liner 

 structural details ol thedc'ii tat e nucK'Us, on 1 he other hand, as well as the expan- 

 sion ot the latt'ral lobes ol the ceri'bellum, establish a gradation which places 

 gorilla m the highest ()osition, with chimpanzee, gibbon, macaeusand baboon 

 succeeding in the order gi\en. Such conclusions are borne out by the size and 

 morphological delimtion ol another cerebellar index, the re<l nucleus. This 

 nucleus has a lunctional signilicance essentially similar to the dentate nucleus. 

 It is largest and best delmed in the gorilla, although its definition and its 

 size in the orang and chimpanzee indicate the high degree to whieh cx)ordina- 

 tivc control has been dcNcloped in these animals. The planimetric and 



