FROG. 109 



(b) The cerebral hemispheres. 



(c) The optic chiasma : ventral to the posterior 



end of the hemispheres. Trace the 

 bundles of fibres as far as possible. 



(d) The tuber cinereum : a shield-shaped body 



posterior to the optic chiasma. On its 

 posterior border attached by a slender 

 stalk : 



(e) The pituitary body. 



(/*) On each side of the pituitary body the 

 crura cerebri : two columns of fibres con- 

 necting the cord and the medulla with 

 the anterior part of the brain. 



4. The Spinal Cord, continued posteriorly from 



the medulla. Note the median (ventral) 

 fissure throughout its length. 



5. The Cavities of the Brain. 



With a razor make a horizontal cut midway 

 between the dorsal and the ventral sides to 

 show : 



(a) In the cerebral hemisphere on each side 



the lateral ventricle. 



(b) Connecting the two lateral ventricles the 



foramen of Monro. 



(c) In the optic lobes the ventricles of the 



optic lobes. 



(d) Connecting (a) and (c) the third ventricle. 



(e) In the medulla the fourth ventricle. 

 B. The Sympathetic Nervous System. 



