CHAP. XVII.] THE BRAIN OF QUADRUMANA. 305 



another small projection (' eminentia collateralis '), which 

 is also recognizable in Man. 



Of the Corpora Quadrigemina the anterior pair are the 

 larger, though they are somewhat less prominent than the 

 other couple. The Pineal Body is rather large and soft. 



In its general shape the inferiority of the brain of the 

 Chimpanzee, as compared with that of Man, is most 

 marked in the direction of vertical height ; in the rela- 

 tively small dimensions of its frontal lobes ; and in the 

 similarly small relative bulk of its occipital lobes. 



The outline of the brain of the Gorilla, as seen from 

 above, is that of a broad ovoid, though it is not so broad 

 as that of the Chimpanzee. Its anterior lobes are wide, 

 rather shallow, bat long, more so even than in the Orang 

 though the latter exhibits a greater complexity of its con- 

 volutions. In vertical height, too, its Hemispheres seem de- 

 cidedly superior to those of the Chimpanzee and the Orang ; 

 but its posterior or occipital lobes are distinctly smaller and 

 shorter than they are in either of the other two ' man -like ' 

 Apes. The parietal lobes of the Gorilla are notable for 

 their great size both in width and depth, while the con- 

 volutions of this region are well define:!, and decidedly 

 more developed than in other parts of the brain. Its 

 ' supra-marginal lobule ' especially, is larger and better 

 defined than it is in either of the other ' man-like ' Apes. 

 The temporal lobes are comparatively smaller, while their 

 convolutions are simple, though not very symmetrical on 

 the two sides. 



Owing to the greater narrowness of its anterior lobes, 

 the outline of the brain of the Orang, as seen from above, 

 is not nearly so rounded as it is in the Chimpanzee, and 

 it is also rather narrower than that of the Gorilla. The 

 anterior lobes are somewhat deficient in length and depth, 



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