SECT. V THE NERVOUS SYSTEM 83 



origin. This difference in the position of the brain in 

 Apus and Limulus is one of those cases, referred to in 

 the preface in which the differences between these tw^o 

 animals afford more striking proof of their relation- 

 ship, through a common origin from a bent Annelid, 

 than any similarity in the position of the brains could 

 have done. 



G 2 



