XI 



BRAIN 



529 



The diencephalon consists of a right and left optic 

 thalamus (o. tli) between which is the slit-like third 



o.th. 



FIG. 141. Two dissections of the Rabbit's brain, from above, (x ij.) In A, the 

 left hemisphere is dissected down to the level of the corpus callosum ; on the 

 right side the lateral ventricle is exposed. In B, the hemispheres are dissected 

 down to a little below the level of the anterior end of the corpus callosum ; only 

 the frontal lobe of the left hemisphere is retained, of the right a portion of the 

 temporal lobe also remains ; the choroid plexus and pineal body are removed, 

 as well as the greater part of the body of the fornix and the whole of its left 

 posterior pillar ; the cerebellum is removed with the exception of a part of its 

 right lateral lobe with the flocculus. 



a. co. auterior commissure ; a. fo. anterior pillar of fornix ; a. pn. anterior peduncles 

 of cerebellum ; b. fo. body of fornix ; cb\. central lobe of cerebellum ; cb*. its 

 lateral lobe ; c. gn. elevation on the optic thalamus ; c. ft. cerebral hemisphere ; 

 ch. pi. part of choroid plexus ; cp. cl. corpus callosum ; cp. s. corpus striatum ; 

 c. rs. and d. p. elevations on the bulb ; fl. flocculus ; hp. in. hippocampus ; 

 m. co. middle commissure ; o. /l, o. 12, optic lobes ; olf. olfactory lobe ; o. tit. 

 optic thalamus ; o. tr. optic tract (continuation of chiasma) ; p, co. posterior 

 commissure ; p.fo. posterior pillar of fornix; pn. pineal body ; pd. pn. its peduncle ; 

 p. pn. posterior peduncles of cerebellum ; p. va. fibres of pons Varolii forming 

 middle peduncles of cerebellum ; sp. lu. septum lucidum ; st. I. line on corpus 

 callosum ; /. s. band of white matter lying beneath choroid plexus ; v. vn. valve 

 of Vieussens ; v'-\ third ventricle ; v*. fourth ventricle. (From Parker's Zoototny.) 



ventricle (v 3 ) roofed over by a thin membrane continuous 

 with a vascular choroid plexus (Fig. 142, vl. ip), and from 



