AMPHINEUBA. 



the chief material for the formation of various organs (circulatory, 

 excretory and genital organs). 



FIG. 4. A C, transverse sections through embryos or larvae (G) of Chiton Polii 

 (after KOWALBVSKY) ; A, through the posterior part of the body of a young embryo, 

 B and O, through the anterior part of the body of more advanced embryos ; au, eye ; 

 c, shell ; coe, coelom ; /, foot ; fd, pedal gland ; In, lateral nerve-cord ; md, 

 enteron ; mes, mesoderm ; pn, pedal commissures ; r, radular sac ; st, spines ; vd, 

 stomodaeum. 



