D.I 



C'a 



M.PI 



Sff> 



FiG. 71. Polygordins neapolitanus. 



A, transverse section of a male specimen to show the position of the 

 immature gonads (spy) and the precise form and arrangement of the 

 various layers represented diagrammatically in Fig. 68, C. 



The body-wall consists of cuticle (Cu), cleric epithelium (Der. Epthtn), 

 muscle-plates (M. Pl\ and parietal layer of ccelomic epithelium (Ccvl. 

 Epthm). The ventral nerve cord ( V. Nv. Cd) is shown to be continu- 

 ous with the deric epithelium. 



The enteric canal consists of ciliated enteric epithelium (Ent. Epthm} 

 covered by the visceral layer of ccelomic epithelium (Ccel. Epthm) : 

 connecting it with the body-wall are the dorsal and ventral mesenteries 

 formed of a double layer of coelomic epithelium, and containing respec- 

 tively the dorsal (D. V) and ventral (V. V) blood-vessels. 



Passing obliquely across the coelome are the oblique muscles (0. M) 



