THE NERVOUS SYSTEM 93 



oval in form, the cerebellum is composed of 

 a row of transverse folia, and carries a small 

 appendage or flocculus on its lateral surface. 



The term peduncles of the cerebrum is applied 

 to those slightly diverging columns of nerve- 

 tissue which form the forward continuation of 

 the medulla oblongata and disappear under 

 the optic tracts and chiasma. Lateral to 

 each peduncle, and between it and the 

 cerebral hemisphere, appears one of the optic 

 lobes from which an optic tract apparently 

 takes origin. 



If the two cerebral hemispheres be separated 

 from each other, two rounded eminences, the 

 thalami, will be revealed ; and behind these 



I is disclosed a small, single, and median object, 

 the pineal body. 



On the ventral surface of the brain there 



i is little difficulty in determining the presence 

 of two optic tracts which appear to be directly 

 derived from the optic lobes. Each tract 

 sweeps forwards and towards the middle line 

 to meet and fuse with its fellow at the chiasma, 

 whence spring the diverging optic nerves which 

 pass to the eyeballs. 



The term hypophysis is applied to a rounded 

 object suspended from the rest of the brain by 



