SECT. V 



THE xNERVOUS SYSTEM 



n 



to us that they belonged to the prostomial com- 

 missures, or stomato-gastric ring, as suggested by 

 Pelseneer, because we considered this ring as no 

 special nerve branching from the cord, but simply as 

 the remains of the original oesophageal commissures. 



eTn- 



Fic. 21.— Central nervous system of Apus. Lettering as in Figs. 17, 18, and 19. 

 cvi, nerve to the eye muscles ; c>, the anterior pair of eyes transformed mto the 

 unpaired " eye " (c/ § on the sensory organs); * the position of the ganglia of 

 the ist pair of antennse according to Pelseneer. 



As for the two transverse commissures, we consi- 

 dered them to represent the two commissures of the 

 two pairs of antennal ganglia. We assumed that each 

 was due to a fusion of two transverse commissures, 

 at least if we might conclude from the fact that the 



