194 



ANIMAL PHYSIOLOGY. 



fibres of the medulla oblongata, with the exception of the 

 restiform bodies, pass up to the cerebrum. 



The cerebellum is a 

 large mass of brain sub- 

 stance covered on the 

 surface with grey matter 

 arranged in complex 

 transverse laminae, with 

 folds of pia mater be- 

 tween them. Its main 

 bulk in the human sub- 

 ject consists of two -large 

 lateral lobes ; but be- 

 tween these, in a depres- 

 sion or vallecula below, 

 there is another portion, 

 the inferior vermiform 

 process ; while above 

 there is an elevation 

 where the lateral lobes 

 Fig. 99. UNDER SURFACE OF BRAIN, meet in the middle, the 

 a, Spinal cord cut across below the super i or vermiform pro- 

 medulla oblongata : on the latter are -, i . 

 seen, from the middle line outwards, CGSS >. and . what S 1V6S a 

 anterior pyramids, olivary bodies, special significance to 

 and restiform bodies, b, Pons Varolii ; these processes is, that 

 c, infundibulum (the pituitary body they correspond with a 

 having been removed) : a. ayn operti, / 77 77 / .7 

 or islLd of Reil; e, section of de- middle l ? be f the cere ' 

 scending cornu of the left lateral bettum in other mam- 

 ventricle, displayed by removal of mals, which in the lower 

 part of the middle lobe of the hemi- orc l ers forms the greater 

 sphere, exhibiting sections of the , f ,1 e .iJri *,, * 

 t^nia hippocampi and hippocampus P art n , ^ staructure. 

 major; /, cerebellum. 1, Olfactory In birds there are no 

 bulb; 2-9, successive cranial nerves, lateral lobes, and in 

 marked each with its proper number, osseous fishes the cere- 

 bellum is reduced to a mesial pouch, without lamination, 

 whose hollow is an expansion upwards of the continuation of 

 the original central canal. In the human subject this hollow 

 is seen in the roof of the fourth ventricle, in front of the in- 

 ferior vermiform process. 



The medulla oblongata, pons Yarolii, and cerebellum, which 



