LESSONS ON SHELLS. 



ON THE MOLLUSCA. 



LESSON I. 



Teacher. Do you know what these things are 

 which I have brought in as the subject of our 

 lesson to-day 1 



Child. They are shells. 



Teacher. Describe to me what you mean by 

 a shell. 



Child. Oh, a shell is that which covers a 

 snail. 



Teacher. Yery true ; a snail has a shell, but 

 in saying this you do not explain to me the na- 

 ture of a shell. When you attempt to describe 

 any thing, you should give such an account as 

 would instruct a person altogether ignorant on 

 the subject. Try again, and tell me what a 

 shell is. 



Child. A shell is a hard covering or house 

 belonging to animals resembling slugs. 



Teacher. Of what use do you suppose shells 

 to be? 



Child. They must be a defence and pro- 

 tection to the animals which they cover. 



Teacher. Yes : shells are the hard coverings 

 of certain animals called mollusca; a name 



