MOLLUSCA. 17 



Teacher. Yes, in animals the glands contain 

 fluids secreted from the blood ; but in vegetables 

 from the sap. Have these animals any fluid 

 answering to our blood ? 



Child. Yes ; but it is white and cold. 



Teacher. In what respects is it similar to 

 blood ? 



Child. It circulates through the body in ves- 

 sels issuing from the heart. 



Teacher. What senses are enjoyed by the 

 mollusca ] 



Child. The senses of feeling, seeing, tast- 

 ing, and, it is supposed, smelling. 



Teacher. In what part of their frames is the 

 sense of feeling most acute ? 



Child. In the tentacula, 



Teacher. Tell me the derivation of that term? 



Child. It is derived from the Latin, Tentare, 

 to try. 



Teacher. But what must they possess in 

 order to be able to feel ? 



Child. Nerves. 



Teacher. I will now read to you a summary 

 of your lesson, and I shall expect you afterwards 

 to write it from recollection. 



Teacher. The mollusca have soft, slimy, 

 cold, fleshy, and contractile bodies. They have 

 no bones, but their shell acts as a support to their 

 frame. They have muscles by which they are 

 attached to their shells, and by which they move 

 their bodies. They are enclosed in a skin called 

 the mantle, or sac, which is full of pores and 

 glands. Sometimes the animal is so completely 

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