330 



THE EARTHWORM 



feather on a central axis (long. mus). Finally, within the 

 muscular layer and lining the coelome is a thin peritoneal 

 membrane (parietal layer, compare p. 26), on the inner 



dors, v 

 typh 



neph 



ext.neph 



neph rost 



n.co 



set 



sub.n.wss 



FIG. 81. Lugubrious, transverse section of the middle region of the'-body. 

 fire. mns. layer of circular muscular fibres ; ccel. coelome ;jcut. cuticle ; dors. v. 

 dorsal vessel ; epid. epiderm ; e.rt. neph. nephridropore \+\hep. layer of yellow 

 cells ; long. mus. longitudinal muscles ; neph. nephridium (shown entire) ; 

 ncphrost. nephrostome ; n. co. nerve cord ; set. setae ; sub. n. vess. sub-neural 

 vessel ; typh. typhlosole ; vent. v. ventral (sub-intestinal) vessel. (From Parker 

 and Haswell's Zoology ', after Marshall and Hurst.) 



surface of which is a very thin layer of cells, the cozlomic 

 epithelium. 



A transverse section of the intestine shows an inner 

 layer of ciliated, columnar enteric epithelium (compare p. 

 109) , a thin middle layer composed of muscle-fibres and 



