72 NATURAL HISTORY. 



number of leaflets or plates of a grayish-white color and 

 folded over each other. The inside of the shell has a 

 slightly iridescent luster, resembling mother-of-pearl. 

 Oysters are found all over Europe, and in Holland are 

 peculiarly fostered. The manner of raising them is as 

 follows : As the young come forth from the spawn from 

 June to the end of August, the oysters are placed in 

 ingeniously-arranged pools, into which the sea water can 

 be admitted at pleasure; here they remain until the 

 young are of a considerable size ; they are then removed 

 from the pools and deposited in suitable places along the 

 coast, which are termed oyster-beds, and thus, gaining 

 time to grow, in the course of four or five years attain 

 full size. They are very small at first, being scarcely 

 the hundredth part of an inch. They live, it would 

 seem, for no other purpose but to subsist on such food as 

 they require, and have no means of defense in time of 

 danger except to close their shell. To secure the first, 

 they must wait with the valves unclosed until the desired 

 object approaches ; but it appears that they can readily 

 distinguish between their legitimate prey and an enemy, 

 for if it is the latter, the shell is immediately shut up. 

 Three mice were once running about on the strand, where 

 some large oysters were lying, and, attracted by the 

 prospect of a good meal, one approached and thrust its 

 nose within the open shell, which the oyster immediately 

 closed, and did not open again until the mouse was dead. 

 The sea crabs are more cunning ; seeing that the oyster 

 closes its shell too quickly for him to effect an entrance,- 

 the wily enemy takes a small stone within his claws and 

 thrusts it between the valves of the shell ; thus keeping 

 it open, he invades the premises fearlessly and feeds upon 



