PIGEON. 125 



(/) The optic cliiasma. 



(g) The infundibulum. 



(h) The pituitary body. 

 Diagram ! 

 2. Section. 



(a) Gently press apart the hemispheres ; note 



that they are not connected. 

 Make a shallow incision in the inner wall of one 

 of the hemispheres near its poster o- dor sal 

 corner so as to open its cavity. Carefully cut 

 away enough of the inner end of the posterior 

 wall to see the whole of the cavity. 



(b) Note the cavity of the cerebral hemisphere : 



the lateral ventricle. Its floor is formed 

 by the corpus striatum. 



Remove the cerebellum by cutting through its 

 peduncles. 



(c) Note : 



(aa) The two optic lobes connected by 



the optic commissure. 

 (bb) Anterior to the optic lobes the paired 



optic thalami. 

 (oc) Between the optic thalami the third 



ventricle. 

 (dd) Anterior to the optic thalami is the 



anterior commissure, and posterior 



to them is the posterior commissure. 

 (ee) Posterior to the optic commissure is 



the fourth ventricle. 



