FKESH-WATER AQUARIUM. 73 



useful little snails. They exhibit a curious mode of tear- 

 ing off a piece from the molluces, which shows that they 

 cannot have very sharp teeth. They will seize on a por- 

 tion of the foot, for instance, which is projecting beyond 

 the shell, and, making themselves perfectly rigid and per- 

 pendicular to the bottom of the tank, spin around with 

 about the velocity of one hundred revolutions per minute, 

 until they have wedged the snail between two stones, 

 when the portion is torn off, and the eel, like his near 

 relation of the land, the boa-constrictor, will lay himself 

 at length at the bottom of the tank until the morsel 

 has passed into his capacious stomach, when he will again 

 attack the snail — although he will rather choose another 

 living specimen, thus seeming to destroy them from pure 

 spite, and in revenge for his confinement, leaving their 

 carcasses to decay and upset the economy of- our well 

 balanced collection. It is for this reason I assert that 

 they are unfit for the fresh-water Aquarium. 



