Batrachian Study 



195 



upper and lower jaws, the latter being below and back of the former. The 

 upper jaw moves back and forth slightly and rythmically, but the drop- 

 ping of the lower jaw opens the mouth. There are three rows of tiny 

 black teeth below the mouth and one row above ; at the sides and below 

 these teeth are little, finger-like fringes. Fringes, rows of teeth and jaws 

 all work together, up and down, out and in, in the process of breathing. 

 The nostrils, although minute, are present in the tadpole in its early 

 stages. The pupil of the eye is almost circular and the iris is usually 

 yellow or copper-bronze, with black mottling. The eyes do not wink nor 

 withdraw. The breathing-pore on the left side, is a hole in a slight 

 protuberance. 



At first, the tadpoles of the frogs and toads are very much alike; but 

 later, most of the frog tadpoles are lighter in color, usually being olive- 

 green, mottled with specks of black and white. The frog tadpoles usually 

 remain much longer than the toads in the tadpole stage, and when finally 

 they change to adults, they are far larger in size than the toads are, when 

 they attain their jumping legs. 



Frog's eggs. 

 LESSON XLVII 

 THE FROG 



Leading thought The frog lives near or in ponds or streams. It is a 

 powerful jumper and has a slippery body. Its eggs are laid in masses of 

 jelly at the bottom of ponds. 



Method The frog may be studied in its native situation by the pupils 

 or it may be brought to the school and placed in an aquarium ; however, 

 to make a frog aquarium there needs to be a stick or stone projecting 

 above the water, for the frog likes to spend part of the time entirely 

 out of water or only partially submerged. 



Observations i. Where is the frog found? Does it live all its life in 

 the water? When found on land how and where does it seek to escape? 



2. Compare the form of the frog with that of the toad. Describe 

 the skin, its color and texture. Compare the skin of the two. 



3. Describe the colors and markings of the frog on the upper and 

 on the under side. How do these protect it from observation from above ? 

 From below? How do we usually discover that we are in the vicinity of a 

 frog? 



4. Describe the frog's ears, eyes, nostrils and mouth. 



5. Compare its "hands and feet" with those of the toad. Why the 

 difference in the hind legs and feet? 



