THE NERVOUS SYSTEM. 



293 



3. Occipital lobe, lies at the posterior aspect of the cerebrum and 

 is divided into first, second, and third occipital convolutions. 



4. Temporo-spJienoidal lobe, occupies the middle fossa of the skull. 



. - * -Sul. tem 



p, nj* 



FIG. 135. 



Inferior aspect of cerebral hemisphere. Sul. olf., olfactory sulcus ; 

 Sul. temp, inf., inferior temporal sulcus; Fis. col., Collateral fissure. 

 (After Van GehucJiten.) (Whitehead.) 



5. Island of Reil, or central lobe, lies within the fissure of Sylvius. 

 It consists of six convolutions the gyri opcrti. 



6. The liinbic lobe surrounds the corpus callosum. Its extremities 

 are united by the roots of the olfactory tract. 



