370 SPECIAL ANATOMY. 



The Parts of the Cerebellum. 



621. I. On the hemispheres. 



1. The superior lobes. They are, an anterior layer, and a poste- 

 rior crescentic ; both are separated by the sulcus horizontalis from 



2. The inferior lobes. These exist in greater number according 

 as they are arbitrarily divided. We usually distinguish an anterior 

 (lob. biventer), posterior, middle lobes, and 



a. Tonsitta (s. lobus medullcz oblongatce) ; lying, generally, in- 

 ternally in a depression on the anterior and middle lobes, be- 

 hind and close to the corp. restiforme of its side, surrounding 

 with its internal concave surface the medull. oblongata, and 

 extending, with its anterior extremity inwards, into the fourth 

 ventricle. 



b. flocculus (lobul. nervi pneumo-gastrici), placed behind the 

 cms cerebelli ad pontem and JV. vagus, below Nn. facialis 

 and acousticus, before the tonsilla. 



3. The. medullary body of the hemispheres. In the interior of 

 each hemisphere we find a white nucleus, from which fifteen to six- 

 teen principal branches pass off, which again ramify, are sur- 

 rounded by a brown substance, and thus produce the arbor vitce. 

 From the central point of the vertical, olive-shaped nucleus, corpus 

 rhomboideum s. ciliare, the indented surface of which is formed of 

 yellow and gray substance, pass out 



4. The crura cerebelli, of which there are three upon either side. 



a. C. cerebelli superiora (s. ad corp. quadrigem., ad testes), are 

 placed before the superior vermis, pass, united, through valv. 

 Vieussens., converging upwards and forwards under ihecorpp. 

 quadrigem., to the cerebrum. 



b. C. cerebelli inferiora s. corpp. restiformia, pass from the 

 medull. oblong, (which see), forwards and upwards, to the 

 hemispheres of the cerebellum. 



c. C. cerebelli lateralia s. ad pontem. They are situated before 

 the two preceding, at the anterior circumference of the cere- 

 bellum, and pass over internally into the pons Varolii. 



622. II. The Vermiform processes, Vermis, 



is the central portion of the cerelxllum, divided by the sulcus hori- 

 zontalis into a superior and inferior portion, contains, likewise, in its 

 interior, a medullary nucleus, from which medullary striae pass into 

 its two divisions. 



1. The superior vermiform process, vermis superior, projects in 



