NERYOUS SYSTEM AND GENERAL SENSATION. 



47 



Fig. 29. The brain of 

 a hare. 



at--- 



Fig. 29 is the brain of a hare (Lepus timidus), seen from 

 above, with the right hemisphere laid open. 1, 1, the ganglia 

 of the olfactory nerves ; a, a, the cerebral hemispheres, without 

 convolutions; b, c, the optic lobes of the right side ; d, the pos- 

 terior border of the corpus callosum ; 

 y the corpus striatum of the right 

 side ; g, the cornu ammonis ; h, the 

 posterior part of the right lateral 

 ventricle ; i, the root of the right 

 optic nerve ; k, the right ganglion of 

 the hemispheres ; /, the cerebellum 

 m, its lateral lobes ; n, the lateral 

 lobules ; o, the medullary laminae at 

 the surface of the cerebellum ; p, 

 the fourth ventricle ; q, the arbor 

 vitse. 



In the ruminantia and carnivora, the convolutions exist as 

 seen in the brain of thecommoncat, (Feliscatus), fig. 30, where 

 1, 1, are the ganglia of the olfactory 

 nerves, and 1*, the cavity which they 

 contain ; 2, the commissure of the 

 optic nerves ; 3, the roots of the third 

 pair ; 8, the roots of the eighth pair ; a, , 

 the anterior lobes; b, the middle lobes 

 of the cerebrum ; a, the white root 

 of the olfactory nerve ; c, the grey 

 matter of the infundibulum ; d, 

 crura cerebri ; e, the pons Varolii ; f, 

 corpora restiformia ; g, corpora py- 

 ramidalia ; h, medulla oblongata ; i, 

 the cerebellum; k, corpora albicantia. Fig- 30. The brain of the cat. 



Fig. 31 represents the brain and spinal cord of the raccoon, 

 (Procyon lotor}. a, the cerebral hemispheres ; 1, the ganglia of 

 the olfactory nerves ; 6, the optic lobes ; c, the cerebellum ; d, 

 the superior, and e, the inferior enlargement of the spinal cord ; 

 f y the cauda equina. The spinal sheath is laid open, to show 

 the cord and the double roots of the spinal nerves. In the 

 rounded brain of the porpoise, and in that of the raccoon (fig. 

 31) and the cat (fig. 30), the convolutions are well developed ; 

 in the brain of the elephant they are deep, numerous, and iso- 

 lated from one another ; the optic thaiami increase in size as we 

 ascend the animal series ^ ;| ^" 



a-. 



