400 DISSECTION OF THE RABBIT. 



iii. The velum medullse postering is a thin membrane 

 forming the roof of the posterior half of the 

 fourth ventricle. 



iv. The cerebellum is attached to the dorsal surface 

 at the junction of the vela medullse anterius 

 and posterius. It consists of an outer layer 

 of grey matter, which is very deeply folded, 

 and a central much-branched mass of white 

 matter, the section having a tree-like appear- 

 ance. 



Fig. 72. Lepus cuniculus. Transverse section of the brain, passing 

 through the widest part of the cerebellum. The shading indicates 

 diagrammatically the distribution of white and grey matter. 

 (a. m. m.) 



A, vermis, or middle lobe of the cerebellum. B, lateral lobe of the cere- 

 bellum, c, floccular lobe of the cerebellum. D, transverse fibres of the pons 

 Varolii, iv, fourth ventricle. 



v. The pons Varolii is seen, in transverse section, 

 crossing the ventral surface of the anterior 

 part of the hind-brain, opposite the velum 

 medullse anterius. 



3. Transverse sections of the brain. 



2/ another brain can be obtained, it should be cut with a 

 razor into a series of transverse sections, about an eighth of an 

 inch thick, and the sections arranged in order in a dish of spirit. 



Such a series of sections affords very instructive 

 views of the mutual relations of the several parts of 

 the brain. 



