THE CRANIAL NERVES. 



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FIG. 84. The base of the brain. The cerebral hemispheres are seen over- 

 lapping all the rest. / olfactory lobes; //, optic tract passing to the optic 

 commissure from which the optic nerves proceed; ///. the third nerve or motor 

 oculi; IV, the fourth nerve or patheticus; V, the fifth nerve or trigeminalix; 

 VI. the sixth nerve or abducens; VII, the seventh or facial nerve or portio dura; 

 VIII, the auditory nerve or portio moll is; IX, the ninth or glosso-pharyngeal; 

 X, the tenth or pneumogastric or vagus; XI, the spinal accessory; XII, the 

 hypoglossal; nc/, the first cervical spinal nerve. 



to form the optic commissure, from which an optic nerve 

 proceeds to each eyeball. 



All the remaining cranial nerves arise from the hind- 

 brain. The third pair, III., (motores oculi, or movers of the 



What is the optic commissure? Where does each optic nerve cro? 

 How many pairs of cranial nerves arise from the hind-brain? 

 Name the third pair. What is their distribution? 



