414 



I feel some degree of confidence in placing the ganglia and the 

 nerves in relation to the rhombomeres and the somites associated with 

 these latter. But I cannot say the same about those in front. 



The VI nerve is clearly derived from two ventral roots connected 

 with the external rectus and the retractor bulbi when that muscle is 

 represented. The IV nerve may be a motor survivor of a mixed 

 ramus, innervating as it does a derivative of a visceral region; it may 

 be compared to the XI. It may be that the III nerve is a polymeric 

 product possibly derived from the ventral roots of the 2nd metasomite 

 and the three succeeding ones, but its history is yet far from clear. 



