THE NERVOUS SYSTEM. 



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divided into two lateral hemispheres connected by a central por- 

 tion, the vermiform process. 



It is composed of univ and white matter the former upon 

 the surface. It is not convoluted, like the cerebrum, but con- 

 sists of a number of thin plates, folia, arranged in a series of 

 crecentric curves, with the concavity forward. 



The cerebellum consists of a central lobe, or vermis, and two 

 lateral hemispheres. The latter are separated on the inferior 

 surface of the cerebellum by a deep hollow, the vallecula, which 

 lodges the medulla oblongata. The floor of the vallecula is 

 formed by the inferior portion of the vermis. 



The incisura cerebelli anterior, separates the hemispheres in 

 front, and rests against the corpora quadrigemina ; 



The incisura cerebelli posterior, separates the hemispheres 

 behind, and receives the upper portion of the falx cerebelli; 



The great horizontal lissure separates the cerebellum into 

 a superior and an inferior surface. 



The upper surface of the cerebellum shows the superior 

 vermis, with its corresponding lobes in the hemispheres. These 

 latter are separated from each other by fissures. The following 

 table gives the arrangement of the lobules : 



Great horizontal fissure. 



Great 



The inferior surface of the cerebellum presents the d-ep 

 depression, the vallecula, which renders the connection between 



