468 



ZOOLOGY 



instrument of the brain and to the development of spoken lan- 

 guage. These three things — the enlarging brain, the free and 



Fig. 246. 



Fig. 246. Skull of adult orang outang. 



Questions on Figs. 244-246. — Enumerate the similarities and the diflferences 

 apparent in these skulls. In what respects is the negro skull intermediate between 

 the orang outang and the Caucasian? Is the difference between the orang outang 

 and human greater in youth or in the adult? What is the probable significance of 

 this? What are the zig-zag lines in some of the figures? What is the meaning of 

 the shaded area above the cheek-bone and back of the eye? How does the lower 

 jaw in the higher races compare with that of the lower? The meaning of this? 



Fig. 247. 



Pig. 347. The outline of the brain of an orang outang. Adopted from Gegenbauer and Vogt 

 and Gratiolet. Front portion. P to 0, cerebrum; C, cerebellum; M, medulla and spinal cord; F, 

 the frontal lobe; P, the parietal lobe; O, the occipital lobe; T, the temporal lobe; R, the fissure of 

 Rolando; S, the fissure of Silvius. 



