O S TR E A. 67 



as to throw it four or five inches at a time. In the 

 water, an equal dexterity is evincetl, by the animal, 

 in raising himself to the surface, directing his 

 course, nd libitum, and suddenly, by the shutting 

 of his valves, dropping to the bottom. 



His less active relative, the rough Oyster, in the 

 mean while, is contented to remain fixed to his first 

 station, surrounded by an innumerable progeny, 

 continually increasing with wonderful fecundity. 

 His motions consist only in turning from one 

 side to the other, which he accomplishes more by 

 sagacity, than any natural agility or inherent 

 strength. He contrives to bolster up one side, by a 

 gradual deposition of soft mud, till he stands nearly 

 upright ; then, availing himself of the flowing or 

 ebbing of the tide, he opens his shell, and is tumbled 

 over by the pressure of the water. As expeditiou 

 is not his object, this mode may answer well. 



It has, however, been observed that the young 

 fry possess the power of swinmiing very swiftly by 

 means of an undulatory motion of the Branchiae. 



It is from the words oWg£<a or oWpsa, terms ap- 

 plied generally to Bivalves by the Greek naturalists, 

 tliat the Latin Ostrea and our Oyster are derived, 

 f2 



