Batrachian Study 



185 



numbers. In winter they burrow deeply in the ground and go to sleep, 

 remaining dormant until the warmth of spring awakens them; then, they 

 come out, and the mother toads seek their native ponds there to lay eggs 

 for the coming generation. They are excellent swimmers; when swim- 

 ming rapidly, the front legs are laid backward along the sides of the body, 

 so as to offer no resistance to the water; but when moving slowly, the 

 front legs are used for balancing and for keeping afloat. 



The song of the toad is a pleasant, crooning sound, a sort of gutteral 

 trill; it is made when the throat is puffed out almost globular, thus form- 

 ing a vocal sac; the sound is made by the air drawn in at the nostrils and 

 passed back and forth from the lungs to the mouth over the vocal chords, 

 the puffed-out throat acting as a resonator. 



The toad has no ribs by which to inflate the chest, and thus draw air 

 into the lungs, as we do when we breathe; it is obliged to swallow the air 

 instead and thus force it into the lungs. This movement is shown in the 

 constant pulsation, in and out, of the membrane of the throat. 



As the toad grows, it sheds its homy skin, which it swallows; as this 

 process is usually done strictly in private, the ordinary observer sees it 

 but seldom. One of the toad's nice common qualities is its enjoyment in 

 having its back scratched gently. 



The toad has many enemies; chief among these is the snake and in 

 only a lesser degree, crows and also birds of prey. 



Reference — The Frog Book, Dickerson; Familiar Life in Field and 

 Forest, Mathews; The Usefulness of the American Toad, U. S. Dept. 

 Agr., Farmers Bulletin, No. 196. 



LESSON XLIV 

 The Tadpole Aquarium 



Leading thought — The children 

 should understand how to make 

 the tadpoles comfortable and 

 thus be able to rear them. 



Materials — A tin or agate pan 

 or a deep earthenware wash- 

 bowl. 



Things to be done — i . Go to 

 some pond where tadpoles live. 



2. Take some of the small 

 stones on the bottom and at the 

 sides of the pond lifting them 

 very gently so as not to disturb 

 what is growing on their surface. 

 Place these stones on the bottom 

 of the pan, building up one side 

 higher than the other, so that 

 the water will be more shallow 

 on one side than on the other; 

 a stone or two should project 

 above the water. 



3. Take some of the mud and leaves from the bottom of the pond, 

 being careful not to disturb them and place upon the stones. 



