Fig. 171e. Anatomy of the oyster, cm, auricle; ve, ventricle; bm, body-mass; 

 cl, cloaca; g, gills; i and i', intestine; I, liver, with its ducts opening into the 

 stomach; M, adductor muscle; i, mouth; rnt, mantle; o, the line of section of 

 figure passing through the stomach; p, outer wrinkled surface of inner or lower 

 palpi; v, vent. After Ryder. 



Fig. 171eZ 1. Young oyster seen from the side immediately after fixation by 

 the mantle-border (wi>; v, ciliated velum, or paddle; 2, four young European oys- 

 ters taken from the beard of the parent, enlarged 06 times; 0, very young spat, 

 showing the peculiar form of the true larval shell and that of the spat > '!"> 

 times; 7, twenty-days-old spat (natural size); 10, young oyster, 2J to 3 months 

 old. After Ryder. 



[To face page 2,33] 



