222 



COMPARATIVE ANATOMY 



individual sections it is more or less comparable to that of certain 

 of the latter (e.g. Chelonia). The basal ganglia (corpora striata) of 



H yp\ 



Tr.opt J/if 

 FIG. 169. BRAIN OF PIGEON. A, dorsal; B, ventral ; and C, lateral view. 



HH, cerebellum ; Hyp, hypophysis ; luf, infundibuluin ; Z.o/, olfactory lobes; 

 Med, spinal cord ; MH, optic lobes ; Nil, medulla oblongata ; Tr.ojtt, optic 

 tract; VH, cerebral hemispheres; I-X1I, cerebral nerves; 1, 2, first and 

 second spinal nerves. 



the hemispheres reach a relatively larger size in Birds than in 

 any other Vertebrates. An advance on Reptiles is seen in the 



