Nervous System. 



A. The Central Nervous System. 



The Brain. 



Carefully remove the fronto-parietals so as to expose the brain, and note 

 the following parts : — 



(a) The olfactory lobes, forming the most anterior portion of the brain, 



united together in the middle line. Anteriorly the olfactory nerves 

 are given off. 



(b) The cerebral hemispheres, a pair of smooth elongated bodies. 



(c) The thalamencephalon, lying immediately behind the cerebral 



hemispheres. It is covered by the choroid plexus, a thick vascular 

 membrane, and gives rise dorsally to the stalk of the pineal body. 



(d) The optic lobes, a pair of oval bodies. 



(e) The cerebellum, a narrow transverse band immediately behind the 



optic lobes. 



(/) The medulla oblongata behind the cerebellum. It gradually tapers 

 towards its posterior end, where it is continuous with the spinal 

 cord. On its roof the pia mater forms a very vascular choroid plexus. 



Make a sketch of the brain. 



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