BIRTH, GROWTH AND REPRODUCTION OF OYSTERS. 9Q 



being an accidental appendage, it is an indispensable 

 provision for the minute oysters, to which, both among 

 animals and vegetables, there are many analogies. Within 

 the husky covering of a grain of wheat, for example, is 

 deposited not only the little germ of the future produce, 

 but the albumen which is to yield it nourishment until the 

 fibrous root it sends forth can derive support from the 

 earth in which it is sown. In like manner, the chick in 

 the egg, finds all that it requires, till the time of its escape, 

 in the yolk by which it is surrounded. 



Now, just what the albumen is to the germ just what 

 the yolk is to the chick, is that floating substance to the 

 little oyster it contains. Even the eye might tell that it 

 fully answers its purpose, but the ear cannot be placed in 

 a sufficiently favourable position to hear the sounds drop 

 drop drop, though, at a certain crisis, the minute 

 creatures must have received so much nutriment as to 

 become too heavy to float, and therefore fall, in succession, 

 into the depths beneath. 



The first circumstance in the oyster's history, after 

 falling from the surface of the waves, was its adhesion to 

 the rock which was to be for a time its dwelling place. 

 How then could this be produced ? The common mussel 

 obtains a mooring to its bed by a silken cable which it has 

 the power of spinning for this purpose ; and, strange to 

 say, this very byssus or beard, has been employed to give 

 strength to the works of man. At a long bridge over the 

 Torridge river, in the county of Devon, the tide flows so 

 rapidly that mortar or cement failing to keep it in repair, 

 the interstices are filled with mussels, whose strong threads 

 fixed to the stonework prevent the bridge being driven 

 away ; and so important is the aid of these little creatures 



that to remove them, except in the presence of the corpo- 



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