INTRODUCTION. D 



ger of trusting his paws between the shells, artfully drops 

 a stone or two into them, which entirely prevents their 

 being closed by the fish; by this expedient he is enabled 

 to extract his prey without danger or difficulty, and de- 

 vour it at his leisure. 



Tortoises and turtles consume numbers of shell-fish, 

 and the strength of their jaws (as reported) is so great, 

 that they can with facility macerate the strongest and 

 roughest shells. 



Birds also, (sea-fowl especially), are great devourersof 

 shell-fish ; and when they are unable to penetrate the 

 shells by their beaks, they ascend with them to a consi- 

 derable height, and let them fall on some rough or craggy 

 place; by which means the shells are broken, and the 

 fish becomes an easy victim*. 



Crabs, and other crustaceous animals, are known to 

 make serious attacks on the testaceous orders. The lar- 

 ger sort of crabs are able, by their great strength, to 

 open the valves of most shells by main force; but those 

 of smaller dimensions make their inroads in a different 

 manner: the pea-crab, in particular, is very destructive 

 to bivalves, especially to muscles; it enters their shells 

 whenever it has the opportunity of finding them open, 

 and there remains, preying upon the fish, till it has cn- 



* Mr. Mawe states, in his Travels in Brazil, that he saw a spot 

 of bare granite, not more than one hundred jards square, covered 

 with an immense number of mutilated shells : the whole neighbour- 

 liood was rich in wood and verdure, and the sea at least five miles 

 distant. On enquirj' he was informed, that large flocks of birds eve- 

 ry evening repaired to this place with shells left by the tide, which 

 they let fall on the rock, in order to obtain their contents. 



