i8 



THE NERVOUS SYSTEM 



fissure posteriorly by the lingual gyms (Fig. 9). The latter 

 is believed by some authorities to contain the higher centres 

 for the sense of taste. 



The other cortical areas on the basal surface of the brain 

 need not be specially described, since little is known with 

 regard to the functions which they subserve. 



18 



FIG. 9. Medial Aspect of Right Cerebral Hemisphere 

 17. Uncus. I 20. Collateral fissure. 



77. Uncus. 



19. Calcarine fissure. 



20. Colls 



21. Lingual gyrus. 



The Mesencephalon or Mid-Brain, which forms the upper- 

 most part of the brain-stem, constitutes the connexion 

 between the cerebral hemispheres and the pons. It consists 

 of the four corpora quadrigemina, which lie on its dorsal aspect, 

 and the cerebral peduncles^ which are partially separated from 

 one another anteriorly by a deep notch. The upper pair of 

 the corpora quadrigemina are connected with the optic tracts 

 (p. 51), while the lower pair are connected with the auditory 

 tracts (p. 89). The cerebral peduncle consists of a dorsal 

 part or tegmentum^ which is continuous across the median 

 plane, and a ventral part or basis pedunculi (crusta\ which is 



