58 MORPHOLOGY OF THE ORGANS OF VERTEBRATES. 



Cranial Nerves. Like the cord, the brain gives rise to 

 nerves, but these nerves present many differences from those 

 of the spinal region. The last word concerning these has yet 

 to be written, but the following outline summarizes our present 

 knowledge, as well as indicates some of the directions in which 

 modifications of our ideas may be expected. 



ncl 



FIG. 60. Base of human brain (from Martin), showing roots of cranial nerves, 

 I-XII. ncl, first cervical nerve. 



The nerves arising from the brain (cranial nerves) are in 

 pairs, which have received names and numbers in man ; and 

 these have been transferred to the corresponding structures in 

 the lower vertebrates as follows : 



I. Olfactory. 

 II. Optic. 

 III. Oculomotor. 



