1883.J 



on Oysters and the Oyster Question. 



349 



imitate these conditions — and to place their breeding stock under 

 circumstances in which hurtful influences shall be excluded, while the 

 larvae are prevented from wandering too far and facilities are afforded 

 for their attachment. 



It has been seen that the young animal which is hatched out of 

 the egg of the oyster is extremely unlike the adult, and it will be 

 worth while to consider its character more closely than we have 

 hitherto done. 



Under a tolerably high magnifying power the body is observed to 

 be inclosed in a transparent but rather thick shell, composed, as in 

 the parent, of two valves united by a straight hinge (Fig. 3 A. h). But 

 these valves are symmetrical and similar in size and shape, so that 



Fig. 3. 



The larva of the Oyster. 



A, side view. B, front view. v. velum with its long cilia ;' o. oesophagus or 

 gullet; St. stomach; r.L, l.l. right and left lobes of the -liver ; ^ intestine ; 

 an. vent; a. add. anterior adductor muscle which alone exists in the larva; 

 r.s., r.i. superior and inferior muscles which retract the velum into the shell, sh. ; 

 h. hinge of the shell. 



the shell resembles that of a cockle more than it does that of an 

 adult oyster. In the adult the shell is composed of two substances 



