342 



DISSECTION OF THE EABBIT 



c. The thalamencephalon is covered by the hemi- 



spheres, and cannot be seen from the dorsal 

 surface. 



d. The corpora quadrigemina, or optic lobes, are two 



pairs of rounded elevations on the dorsal surface 

 of the brain, and almost completely covered by 

 the hemispheres. 



e. The cerebellum is a large transversely elongated 



mass, lying behind the hemispheres. It is divided 

 into a large median lobe, the vermis, and two 



F.M 



C.H 



V.P 



IV 



C.A 



FIG. 43. Lepus cuniculus. A longitudinal and vertical section of the 

 brain, taken in the median plane. (A. M. M.) 



A, pituitary body. AC, anterior commissure. A3T, anterior pillar of the 

 fornix, seen in the wal] of the third ventricle. C, cerebellum. CA, corpus 

 albicans. CC, corpus callosum. CH, inner surf ace of left cerebral hemisphere. 

 IP, body of the fornix. FM, foramen of Monro. GK velum interpositum. 

 I, infundibulum. MC, middle commissure. N, anterior lobe of corpora 

 quadrigemina, or ' nates.' O, olfactory lobe. OC, optic chiasma. ON, left 

 optic nerve. P, pineal body. PC, posterior commissure. PV, pons Varolii. 

 T, posterior lobe of corpora quadrigemina, or ' testis.' V A, velum medullse 

 anterius, or valve of Vieussens. VP, velum medullse posterius. 



Ill, third ventricle. IV, fourth ventricle. V, fifth ventricle. 



lateral lobes ; to the outer sides of which are the 

 small rounded floccular lobes. 



The whole surface of the cerebellum is marked 

 by close-set folds, mainly transverse in direction. 



