200 THE WORLD OF THE SEA. 
say that they have not sympathies which may affect the whole 
bank. 
The oysters’ powers of locomotion are exceedingly simple and 
imperfect; frequently they are riveted to the spot where they 
were deposited as infants. The only organ of motion is situated 
immediately beneath the heart. The substance of this muscle is 
white flesh, which passes through the mantle on each side, and 
attaches itself to the centre of the valves. This is the muscle 
which is cut by the fishmonger when he wishes to open the oyster, 
and we again mutilate it when we consume the delicate mollusk. 
When the animal chooses to contract this muscle, the shell is 
A GROUP OF OYSTERS. 
hermetically closed; when it relaxes it, there is an elastic liga- 
ment placed at the hinge of the valves which acts precisely as a 
spring, and opens the shells. It has been asserted that the oyster, 
by rapidly opening and shutting its valves, is able to change its 
place, and even to move from rock to rock; but the assertion 
needs more confirmation. 
The mode in which these mollusks propagate their species is 
very peculiar. The oyster is an hermaphrodite—that is, it unites 
in each individual both sexes. These mollusks are not even like 
flowers of the like nature, for the organs of reproduction are only 
visible at the period of their use. 
The eggs are placed between the folds of the mantle and in 
the midst of the respiratory organs. Their number is prodigious. 
According to Baster, one single oyster can carry 100,000 eggs. 
Poli says 200,000, and Leuwenhoeck even gives the prodigious 
