CHAPTER XII. 

 BRANCH CHORDATA. 



CLASS AMPHIBIA. 

 Example. The Frog. 



Where Frogs Live. Frogs are usually found in or near 

 water. In the spring they congregate in ponds and pools 

 to lay their eggs. Later in the season they scatter, and 

 may be found at some distance from the water, but still in 

 moist places, such as near springs, swampy meadows, etc. 

 Even when they are spending most of the time in the 

 water they come out on the banks to catch insects. 



How the Frog Progresses. The frog has three modes of 

 locomotion jumping, swimming, and creeping or walk- 

 ing. The latter mode is seldom used except to change its 

 position or climb up something on which to rest. The long, 

 muscular thighs enable the frog to make powerful leaps, by 

 which it rapidly escapes to the water when it is on shore 

 and alarmed. In swimming it folds the fore limbs along- 

 side the body and by the simultaneous strokes of the two 

 hind limbs, with the long, broad, webbed feet, makes rapid 

 progress. It is a model swimmer. 



The Frog's Food and Method of Eating. The frog 

 feeds chiefly on insects, though it also eats slugs, worms, and 

 various kinds of larvae. The writer has found the remains 

 of a mouse in the stomach of the common frog, and in the 

 stomach of a bullfrog a small bird entire ; but these cases 

 are exceptional. The frog catches insects its main 



181 



