FISHES IN GENERAL. 127 



hear, as carp may be trained to assemble at the 

 sound of a bell. 



Fish are produced from eggs, and in amazing 

 numbers ; a single fish often containing many thou- 

 sand eggs, roe, or spawn, as they are termed. 

 Many kinds migrate, as the period for spawning 

 approaches, to great distances, often crossing wide 

 seas, in order to reach fit places for this process. 

 The eggs are laid in the sand or gravel, and 

 hatched by the warmth of the sun. The young 

 fish, or/ry, are capable of supporting themselves 

 the moment they leave the egg ; and governed 

 by a wonderful instinct, though they have never 

 known a parent, they have immediately the same 

 habits, seek the same haunts, and take the same 

 means to defend themselves. 



Fish live to a great age, and many of them 

 attain considerable sizes. 



Questions. 



What creatures form the fourth class in the animal king- 

 dom 1 



In what respect do they differ from the first three classes ? 



What organs have fish in the place of lungs ? 



Are the forms and coldurs pleasing ] 



Are they social in their habits 1 



What is their general character ? 



Have fish eyes like our own 1 



Have they voice 1 



In what way are the young of fish produced 1 



How are the eggs or spawn hatched ? 



What is singular about the fry, or young fish 1 



