XIII 



PHYLUM CHORDATA 



439 



with certain differences, of which the following are the most 

 important. 



The surface of the cerebral hemispheres (Fig. 1031, /. I., 

 Fig. 1032, c. li.\ which are relatively long and narrow, presents 



S*. - 



m.b. 



md. 



IV AN :;- A-TTT 



11 



p.v. vi vii ix 



Xll 



FIG. 1031. Lepus cuniculus. Brain. A, dorsal view ; B, ventral ; C. lateral, b. o. olfactory 

 lobe; cb', median lobe of cerebellum (vermis) ; cb". lateral lobe of cerebellum; cr. cauro- 

 cerebri ; tp. epiphysis ; j\b, parencephala ; /, p, longitudinal fissure ; h.b. hind-brain ; hp. hype - 

 physis ; m.b. mid-brain" (corpora quadrigemiiia) ; md. medulla oblongata ; p. r. pons Varolii ; 

 I XII, cranial nerves. (From Wiedersheim.) 



certain depressions or sulci, which, though few and indistinct, 

 yet mark out the surface into lobes or convolutions not distin- 

 guishable in the case of the Pigeon or the Lizard. A slight 

 depression the Sylvian fissure at the side of the hemisphere 

 .separates off a lateral portion, or temporal lobe (Fig. 1033, c. 7i 2 .), 



