OILL.S 



387 



bodies on each side between the visceral mass and the 

 mantle : we have thus a right and a left outer, and a riglit 

 and a left inner gill (Fig. 95, ext. gl, int. gl.). Seen from 



_ u i: rt n ^ 3 •>; Vj = D. ,-j n 



the surface (Fig. 93), each gill presents a delicate double 

 striation, being marked by faint lines running parallel with, 

 and by more pronounced lines running at right angles to, 



C c 2 



