52 



FIRST LESSONS IN ZOOLOGY 



of the locust sec Comstock and Kelloi;-g's " Elements of 

 Insect Anatomy," Chap. II. 



The pond snail. — Pond snails may be found in almost 

 an)' pond, and live si)ecimens ma}' be easily kept in the 

 schoolroom aquarium or simpl)' in bowls or glass jars 

 of water (fig. 30 ). They should be fed pieces of lettuce 

 or cabbage leaves. Observe the habits of the snails; 



Fig. 30. — Pond snails in a battcrv-jar aquarium. (Oiit^ third natural 

 size; from liJr. ) 



how the)' come to the surface to breathe ; how the)' crawl 

 about; how they eat by rasping off bits of the leaves 

 with the rough, horny tongue; how the)' protrude from 

 and withdraw into the shell; how the feelers move in 

 and out. 



l^xamine a specimen with bod)' extended from the 

 shell, and note that it is not made up of segments or rings, 

 but is a soft, unsegmented mass with a firm, muscular, 

 flattish tlisk on its lower side called the foot. How does 



