xn.] 



THE mND-BRAIN. 



369 



lobe with an arbor vitsB, into which the fourth ventricle 

 is prolonged. There are two small lateral lobes, ap- 

 parently equivalent to the flocculi. 



In Mammalia the cerebellum attains a still greater 

 development. The median lobe or vermiform process 



Fio. 119. 



42^ Cfis in/ 'u^ fin^ 



LONOITUDINAL SECTION THROUGH THE BeAIN OF A ChICK OP 



Ten Days. (After Mihalkovics.) 



hm^. cerebral hemispheres ; alf. olfactory lobe ; aZ/i, olfactory 

 nerve ; ggt. corpus striatiun ; oma. anterior commissure ; 

 chd 3. choroid plexus of the third ventricle ; 'pin. pineal 

 gland ; cnvp. posterior commissure ; trm. lamina terminalis ; 

 chm,. optic chiasma ; inf. infundibiilum ; Ivph. pituitary body ; 

 hgm. commissure of Sylvius (roof of iter a tertio ad quartum 

 ventrioulum) ; vma. velum medullse anterius (valve of Vieus- 

 sens) ; M. cerebeUimi ; chd 4. choroid plexus of the fourth 

 ventricle; dbt 4. roof of fourth ventricle ; 06?. medulla oblon- 

 gata ; pM. commissural part of medulla ; inv. sheath of 

 brain ; his. basilar artery ; arts, internal carotid. 



F. & B. 24 



