78 THE OYSTER. 



PLATE V. 



Oysters fastened to the upper surface of a round 

 boulder, which had formed the ballast of some vessel 

 and had been thrown overboard in the bay, where the 

 lower half had become embedded in the bottom. The 

 figure, which is about one-fourth the size of the speci- 

 men, shows the way in which the oysteis grow, in 

 dense crowded clusters, on any solid body which raises 

 them above the mud. 



