SECT. V 



THE NERVOUS SYSTEM 



77 



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 cesophageal commissures. 



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

 cm, nerve to the eye muscles ; e*, the anterior pair of eyes transformed into the 

 unpaired " eye " (cf. on the sensory organs); * the position of the ganglia of 

 the ist pair of antenna; 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 



