124 ZOOTOMY. 



'Its dorsal surface is marked with an obscure longitudinal furrow, 

 continuous with the dorsal fissure of the cord, and separating two 

 longitudinal elevations, the posterior pyramids, external to which are 

 two similar elevations, the restiform bodies. 



185. The cerebellum icrb), a large tongue-shaped 

 body, lying on the dorsal side of the medulla oblongata, 

 and largely concealing it in a view from above. The medulla 

 and cerebellum together form the hind-brain. 



186. The mid-brain, consisting on the dorsal side of 

 two considerable ovoidal massss, the optic lobes {o.l), 

 and below of a mass corresponding to the crura cerebri 

 (c.c), of other vertebrate brains. 



187. The fore-brain, consisting mainly of the two 

 cerebral hemispheres (it./z), irregular rounded masses, 

 situated just anterior to the optic lobes, and of considerably 

 smaller size than the latter : each hemisphere is marked 

 dorsally with a furrow or sulcus parallel to its inner edge. 

 A small somewhat rhomboidal area in the middle line, 

 between the hemispheres and optic lobes, is all that appears 

 externally of the 'twixt-brain or thalamencephalon, 

 above ; below it is constituted by two somewhat bean-shaped 

 bodies, the lobi inferiores (/.«), and the infundibulum 

 (//;), lying between them (see § 205). On slightly separating 

 the hemispheres they are seen to be united by a delicate 

 transverse commissure- (^ot) passing between their inner faces. 



188. The pituitary body {pt), a rounded vascular mass, 

 of deep red colour, situated in the middle ventral line 

 immediately beneath the thalamencephalon. 



189. The olfactory lobes {olf), two rounded bodies, 

 each about two-thirds the diameter of one of the cerebral 

 hemispheres, situated in close contact with the hinder walls 

 of the nasal sacs, and connected hy dehcate nerve-like cords 

 (I) with the corresponding hemispheres : the connecting 



