BATRACHIA 



129 



surface when it floats or swims in a tub of water ? Why ? 

 Do frogs croak in the water or on the bank ? Why do 

 they croak after a rain ? Do toads croak ? 



Are the eggs laid in still or flowing water ? In a clear 

 place or among sticks and stems ? Singly, or in strings or 

 in masses ? (Fig. 248.) Describe an egg. Why do frogs 

 dig into the mud in autumn in cold climates ? Why do 

 they not dig in mud at the bottom of a pond ? Why is 

 digging unnecessary in the Gulf states ? 



FIG. 250. PAINTED FROG ( Chorophilus ornatus) , of Mexico. 



Describe the position of the frog when still (Fig. 250). 

 What advantage in this position ? Does the frog use 

 its fore legs in swimming or jumping ? Its hind legs ? 

 How is the frog fitted for jumping'? Compare it in this 

 respect with a jumping insect; a jumping mammal. How 

 is it fitted for swimming ? Is the general build of its body 

 better fitted for swimming or jumping ? How far can a 

 frog jump ? 



External Features. The frog may be said to have two 

 regions in its body, the head and trunk, A neck hardly 



