MAMMALIA. 197 



FIG. III. 



THE MONKEY. 



(SIMIA.) 



IT shows the base of the brain and the origins of the nerves ; also the small 

 olfactory nerves ; the small trapezoid bodies, the olivary bodies, and the lateral lobules 

 of the cerebellum. The posterior horn of the lateral ventricle is not of the same small 

 size in every species of simise, but varies with the size of the posterior lobe of the 

 brain. 



FIG. IV. 



THE HORSE. 



(EQUUS CABALLUS.) 



IT shows the base of the brain, and the origins of the nerves. 



1. Olfactory nerve ; its origin occupies a considerable part of the surface of the 



base of the brain, and is connected with the inferior part of the hippocampus. 

 It forms a large bulb, which is placed over the cribriform plate of the 

 ethmoid bone, and terminates in branches passing through the perforations 

 in this to the Schneiderian membrane of the nose. 



2. Commissure of the optic nerves, after the surface of the thalamus anteriorly has 



received the termination of the true visual tract ; in passing posteriorly the 

 optic tract becomes connected with the surface of the nates, the geniculate 

 bodies, and with the mammillary body and the prominence surrounding it. 



