20 LESSON III. 



carnivorous * mollusca have usually a kind of pro- 

 boscis ; this instrument is a fleshy pliable tube 

 terminated by a round aperture, with a cartilagi- 

 nous edge armed with little teeth, f The proboscis 

 is supplied with muscles, by means of which the 

 animal can protrude or draw it in at pleasure ; 

 many use it to pierce other shells, that they may 

 suck out the flesh of the inhabitant. I have men- 

 tioned to you three different kinds of mouths 

 which mollusks are found to possess ; describe 

 them to me. 



Child. Some have only a simple opening, 

 others have jaws, either of a horny substance, or 

 armed with teeth; and others possess a pliable 

 fleshly proboscis, moved by muscles, and termi- 

 nated by a cartilaginous ring which has teeth. 



Teacher. Which are the feeders upon vege- 

 tables, and which upon animals ? 



Child. The mollusks which have a muzzle 

 feed upon vegetables, those with a proboscis are 

 carnivorous. 



Teacher. In feeding there is another point to 

 be considered, how the food is to be brought to 

 the mouth ? How do we manage this operation ? 



Child. By means of our hands ? 



Teacher. And what makes it particularly 

 needful that man should possess hands? 



Child. His erect position. 



Teacher. You have often had an opportunity 



* From the Latin carne, flesh, and voro> 1 eat. 

 f Voluta. 



