The Nervous System of Worms 69 



en. 



n.c. 



nervous matter extends along the length of 



the body; at each somite the cord swells 



into a ganglion from which nerves pass 



t o neighbouring 



structures. These 



nerves contain in- 



coming (afferent) 



fibres or paths, by 



which impressions 



made on the surface 



of the animal's body 



are conducted to the 



central ganglion, 



and outgoing fibres 



(efferent) commenc- 



ing in the ganglion 



and terminating in 



effective structures 



such as muscles or 



glands. The class 



. i i FIG. 10. Diagram of nervous system 



OI bemgS tO Which of Annelida. 5, brain ; c.n., cephalic 



. 1 nerves to supply sense organs of 



belong, anterior end of the worm ; n.c., nerve 



, cord passing from the brain to s.e.g., 



US not Only the sub-cesophageal ganglion; s.g., 



i -f tU segmental ganglia giving off nerves 



an example OI tne to the corresponding segments of the 



way in which their body ' (H " raa p n ,f|.f h ' Fig ' 3 ' 



WOrmS 



