THE BRAIN 



175 



so that an anterior, a -posterior, and an inferior cornu can be dis- 

 tinguished in each ; the inferior cornu extends into what corresponds 

 to the hippocampal lobe of Reptiles (p. 168), and an eminence on 

 its floor, known as the hippocampus major , is much more marked 

 than in lower forms. The olfactory lobes, in which an olfactory 



r TZT 



Rol 



FIG. 144. BRAIN OF DOG (POINTER). (A, dorsal; B, ventral; and C, 

 lateral view.) 



VH, cerebral hemispheres ; MH, optic lobes ; HH, cerebellum , Wu, superior 

 vermis ; HH 1 , lateral lobe of cerebellum ; NH, medulla oblongata ; Mtd, 

 spinal cord; Hyp, hypophysis; Po, pons Varolii : Cr.ce, crura cerebri ; 

 Fi.p, pallial fissure ; B.oi, olfactory bulb ; I-XII, cranial nerves. 



tract and bulb can be distinguished, usually extend forwards freely 

 from the base of the prosencephalon and each may (e.g., Horse) 

 contain a prolongation of the lateral ventricle ; but in some cases 

 (e.g., numerous aquatic forms and Primates) they are completely 

 covered by the frontal lobes. 



