378 



THE RABBIT. 



the hinder ends of the hemispheres thicken still more, to form 

 the corpora striata (Fig. 155, BI), a pair of prominent swellings, 

 lying in front and to the outer sides of the optic thalami, BU, 

 and separated from these by well-marked grooves. 



The hippocampus major (Fig. 152,n) is a prominent curved 

 ridge, projecting into the lateral ventricle, and extending round 

 into its descending cornu ; it is really an inwardly projecting 



F.M 



C.H 



V.P 



[\ 



FIG. 153. A longitudinal and vertical section of the brain of an adult Rabbit, 

 taken jn the median plane. (From Marshall and Hurst.) 



A, pituitary Ixuly. AC. anterior commissure. AF, anterior pillar of the fornix. 

 in in the wall of the third ventricle. C, cerebellum. CA, corpus albicans. CC- 



!, optic chiiistna. ON, left optic nerve. P, pineal body. PC, posterior commissure. 

 v ", JHIIIS Varolii. T. (posterior lobe of corpora quadrifreinina, or ' tcstis.' VA, velum 

 ieilu]lw anteriiis, or valve of Vieusseiis. ~VP, velum meilullae postering. 

 III. third ventricle. IV. fourth ventricle. V, fifth ventricle. 



00, 



PV 



fold of the wall of the hemisphere, formed by a deep groove on 

 the surface of its inner wall. 



The choroid plexus of the lateral ventricle (Fig. 155, x) is 

 a somewhat similar, but much thinner fold of the inner wall of 

 each hemisphere, between the two layers of which blood-vessels, 

 XD, pass in freely. It lies immediately below the hippocampal fold. 



The commissural bands between the two hemispheres are 

 very characteristic structures in Mammals, in which they attain 

 a much higher development than in other Vertebrates. The 

 most important of these are the corpus callosum, the fornix, and 



