MOVEMENTS OF THE OYSTER. 



245 



As everybody knows, the oyster is a marine mollusc. 

 It lives close to the shore, and in comparatively shallow 

 water ; attaching itself to the rock, to one of its own kind, 

 or to any object calculated to afford it the support it re- 

 quires. Here its sole exercise would seem to consist in 

 opening and closing its valves ; its only pleasure in eat- 



A GROUP OF OYSTERS. 



ing. Its food is brought within its reach, to some extent, 

 by the motion of the waves, and is formed of animal mat- 

 ter held suspended in the water. Though emphatically a 

 marine mollusc, yet M. Beudant proved, by experiments 

 made in 1816, that it may be trained to live in fresh- 

 water streams. 



