17 



Figure 13: Disposition of organs at base of mantle cavity of the pediveliger of Ostrea edulis 



L. (from Waller, 1981). 



Posterior view: a — anus; b — border between prodissoconch I and II; e — eye; 



obg — opening of byssus gland; osc — opening of statocyst canal; pat — postanal tuft of cilia; 



ppn — pore of protonephridium; rf — rudiment of foot. 



Figure 14: Stretched velum of the deepwater woodboring pholadid Xylophaga atlantica 

 Richards (from Culliney and Turner, 1976). 



