394 



THE NERVOUS SYSTEM 



The cerebellum shows a wrinkled surface different in 

 appearance from the folded cerebrum. Between its lobes 



Olfactory Bulb 



(to which is attached 

 the Olfactory Nerve) 



Pituitary Body _^ 



Optic Nerve 



Optic Chia^ma 



Oculomotor Nerve — 



Trochlear Nerve- 



Trigeminal Nerve 



Pons Varolii 



Ahdticens Nerve- „ 



S'acial Nerve — 



Auditory Nerve- ^ 



Glossopharyngeal Nerve — 



Vagus Nerve — 



Spinal accessory Nerve — 



Hypoglossal Ner^e — 



Medulla Oblongata 



First Spinal Nerve 



Cerebellum — 



Spinal Cord ? 



Second Spinal Nerve- 



Fia. 182 — Human brain viewed from below. 



is seen the lower part of the medulla whose lower end nar- 

 rows and is continued to form the spinal cord. 



Along the under side can also be made out twelve pairs 

 of cranial nerves, two more than in the frog's, brain. The 

 first ten pairs are connected to the same regions as those 

 of the frog and have the same functions. The eleventh 

 and twelfth arise from the medulla and are known respec- 

 tively a.s the spinal accessory and hypoglossal. The spinal 

 accessory is a motor nerve and supplies the muscles of the 

 shoulders. The twelfth, or hypoglossal, is also motor and 



