THE OYSTER 37 



she keeps them in her gills. Then one day she 

 suddenly opens her valves and squirts them out 

 into the water, where they look like a little cloud 

 of the finest possible dust. For a short time after 

 these eggs hatch the baby oysters swim about, 

 and travel backwards and forwards as the tide 

 rises and falls. After a while, however, they sink 

 down and fasten themselves to some object at the 

 bottom of the sea ; and when once they have done 

 this they never move again. They always lie 

 upon their left sides, with the smaller and flatter 

 of the two valves uppermost; and there they 

 remain for five years at least before they reach 

 their full size. 



Oysters feed, too, in a very odd way. You 

 know, perhaps, that inside the shell of an oyster 

 there is a tufted organ which we call the "beard." 

 This consists of the gills. Hidden away under- 

 neath these is the mouth; and the gills do not 

 merely suck out the air which has been dissolved 

 in the water, as those of other animals do, but 

 sift out every little tiny scrap of decaying matter 

 which the oyster can use for food as well. So an 

 oyster's gills enable it to breathe and to catch its 

 dinner at the same time ! 



