SECT. V 



THE NERVOUS SYSTEM 



73 



ganglion. All wc can positively affirm is that, if 

 the ganglion was infra-oesophageal in the Annelid, 

 the proximal portion of the nerve was carried up 

 with the cerebral portion of these commissures 



Fig. 20. — Diagram showing the same as Fig. 19, drawn, however, on the assump- 

 tion that the nerves for the first antennae in the original Annelid came from the 

 posterior end of the brain. Lettering the same as in Fig. 19. X shows the 

 position of the ganglia of the first antennae according to Pelseneer. 



which split off and travelled backwards. This would 

 explain the apparently anomalous position of the 

 points of departure of the antennal nerves from 

 the brain-oesophageal commissure, — they have to cross 

 each other to reach their destinations. As these 



