SHELLS. 39 



stones and weeds which surround them, and thus 

 escape the notice of their enemies. Now tell me 

 the two principles which are to be traced through- 

 out the works of creation. 



Child. The economy of God, and his com- 

 pensatory providence. 



Teacher. Bear these principles in mind, and 

 you will be much interested in seeing many illus- 

 trations of them in the habits of the mollusca. 

 The following lines of Pope will help to fix them 

 in your memories : 



Nature to these, without profusion^ kind, 

 To proper organs, proper powers assigned ; 

 4 Each seeming want' compensated of course, 

 Here with degrees of swiftness, there of force. 



LESSON VIII. 



CLASSIFICATION OF SHELLS. 



Teacher. What do you think will be our next 

 step in the study of shells ? 



Child. To learn the names of shells, and how 

 to class them. 



Teacher. What do you suppose first led peo- 

 ple to adopt classification ? 



Child. The wish to arrange their shells. 



Teacher. This would be one inducement, but 

 there are many more important advantages con- 



