STRUCTURE OF THE NERVOUS SYSTEM 297 



connect the brain with the different parts of the head, 

 neck, and trunk, as follows : 



i. The first pair (olfactory nerves; nerves of smell; 

 afferent) connect with the mucous membrane of the 

 nostrils (Fig. 136). 



-Sp. Cord 



- 1st Sp. Nerve 



- 2d Sp. Nerve 



FIG. 136. Diagram suggesting the distribution and functions of the 

 cranial nerves (Colton). See also Fig. 132. 



2. The second pair (optic nerves ; nerves of sight ; 

 afferent) connect with the retina of the eyes. 



3. The third, fourth, and sixth pairs (mot ores oculi ; 

 cdntrol muscles of the eyes ; efferent) connect with the 

 internal and external muscles of the eyeballs (Fig. 136). 



4. The fifth pair (trigeminal nerves; nerves of feeling 



