SHELLS. 51 



how the shells were enlarged, you called the 

 opening the mouth. * 



Teacher. Yes, it is termed cither the mouth 

 or aperture. 



Child. Shells have also sides. 



Teacher. Yes, and it is necessary that you 

 learn to distinguish the two sides. You are sup- 

 posed, when you describe a shell, to place it 

 upon its base with it mouth turned towards you ; 

 the right side will then be that nearest to your 

 right hand, and the left that nearest your left 

 hand. 



Child* What is the part turned toward me 

 called 1 



Teacher. The front ; and what do you sup- 

 pose the reverse is 1 



Child. The back. 



Teacher. Look at this section of a shell. 



Child. Is it cut down the middle that we may 

 observe the inside 1 



Teacher. Yes ; and what do you perceive ? 



Child. There is a pillar round which the 

 whorls appear to wind. 



Teacher. This pillar is called the Colwnella, 

 from the latin colum e//a, a little column. 



Child. Have we now mentioned all the parts? 



Teacher. No, you must examine your shells 

 more attentively. 



Child. The edges of the mouth. 



Teacher, By what name are the edges or 

 borders of our mouths called ? 



Child. Lip. Is the same term applied to the 

 edges of the mouth of shells ? 



