FIG 1 Ovster with right shell and mantle removed a and «■ origin of 



^,nJlirof The nervous system: g. Kills; gc, cavity between the two mantle folds; 

 f h^nge J Hgamen" ; If! adductol- muscle ; m, mouth ; mt mantle tt.e arrows 

 show the direction of currents produced by the cilia: p', outer end of right pedal 

 musdeTsfexternal opening of sexual and renal organs of right side;.;, anus; »c, 

 ventrjcle of heart. ^ __, „,.„„„, „f fh« «v=t-pr a, duct of sexual 



Fig. 2. Diagram to show sexual 

 gland. Other letters as above. 



ms of the oyster. 



