SUMMARY' OF STRUCTURES 705 



COMPARISON' OF THE INFERIOR OLIXARY BODY OF THE GREAT APES AND THE 



I NTERM EDI A IT-, PRIM ATES 



W hatcxcr signidcaiicc inav \x- attachccl to thrsc clilKTriiccs in the hi<iher 

 anthropoids Ix'conu'S greatlN increased hy coni|)arin<i ihein with the iiitcr- 

 mediati' primates. The inlerior oh\ary body ol the great apes has a pro- 

 nounced ad\anta<,ie in size ()\(.'r the internu'thate group. Nor is size aloin' the 

 only superioritx in this comparison. 1 he morphological delinition and degree 

 ol coiudlution m the macacus, Ijaboon ami gi Ijbon are lar mlerior to thes 

 aspects ol the inkrior oli\t' m the largt'r anthropoids. In one instance only 

 is there any semblance ol an a|)|)ro\imation to the standard ol tlu' great apes 

 namely, in the gibbon. Conditions underl\ing the olixary dillerentiation in 

 gibbon ha\'e pre\Tously been considered. This animal's exacting need ol close 

 coordination between eye and hand m its llight-hke passage through the 

 trees has already been noted. E\en with this exception, the dilk'rcnce is so 

 marked as to dis[X'l any reasonable doubt concerning the I'xolutional unlokl 

 ing in the olivary adxanci' Irom the intermediate primates to the higher 

 anthro[:)oids. 



COMPARISON OF THE INFERIOR OLI\ARY BODY OF THE GREAT APES AND THE 



LOWER PRI.MAIES 



The dilVerence between the great anthropoids and the lower ])rimates 

 in respect to the inferior oli\ar\ body sup|)lies tiie Imal argumeiu, il such 

 were nei'ded, to maintain that a progressive structural t'X|)ansion has bcx'ii in 

 process from the lowl\ beginning of the |3rimate kind, through its intermedi- 

 ate stages up to its higlu-r dillerentiations. The planimetric coellicient of 

 tarsius, standing at the lowest extremit\ of the ])rimate ordi'r, is represented 

 by the low \alui' of 4 per cent, while the gorilla's corresponding ])laniinetric 

 coeiriclent is 18.6 per cent. This dillereiux' bt-twcen the lowest and the highest 



