568 



THE HIGHER ANTHROPOIDS 



the lateral surface into two nearly I'cjual areas and presents an uj)i)er and a 

 lower genu, and the marked sulcus suniariini which is continuous on the 

 mesial surface with the sulcus in the human hrain known as the parieto- 



FIG. 253A. LEFT LATERAL SURFACE OF BRAIN, CHLMPANZEE. 



(Actual Length 100 mm.) 



occipital fissure. These fissures separate the frontal Ironi the parietal, 

 the parietal from the temporal and the parietal iVom the occipital lobes, 

 thus establishing definite boundaries lor a distinct lobational design on the 

 lateral surface of the hemisplu're. As is the case with all ol the great apes, 

 the richest coinolution ap|)ears in the parietal area, or somesthetic region of 

 the brain, within which the syntheses of bod\ sensation ari' I'laborated. The 

 coin'olutional pattern of tiie frontal lobe is also rich, although considerably 

 less than in man. All of the frontal coiuolutions ol the human brain may be 

 discerned; some ol them, ho\\f\er, onl\ incompletelx outlined by secondary 

 frontal fissures. The complexity ol coiuohitional design m the brain ol 



