30 LESSON V. 



Child. Most of them in the sea, but some on 

 land, and others in ponds and rivers. 



Teacher. Those which live on land, are called 

 terrestrial, from the Latin, terr #, earth. These 

 mollusks feed on vegetables, and have always four 

 tentacula, and their eyes are placed at the tips of 

 these organs. The shells which are found in 

 fresh water, are called flumatile, from the Latin 

 fluvi us, a river ; they are generally of a corneous 

 colour, and are semi-transparent ; their mollusks 

 have only two tentacula, which are flat, having 

 eyes at the base. The shells inhabiting the sea 

 are termed marine, from the Latin, mar e, the 

 sea ; they are much the most numerous, the most 

 beautiful and the most highly prized. I will now 

 recapitulate to you the substance of the lesson of 

 to-day, and you must write it on your slates.* 



SUMMARY. 



Shells resemble the hard coverings of insects ; 

 the principal difference between them is, that the 

 former are only attached to the animal in one or 

 two places, while the hard case of insects fits the 

 members of their bodies, and has more of the 

 nature of a skin. The substance also differs ; that 

 of shells is a carbonate of lime, with a small por- 

 tion of an animal substance called gelatine, and is 



* It would be desirable before the recapitulation, that the 

 teacher should question the pupils upon the points that have 

 been discussed, as in a preceding lesson. 



