94 
AMPHIBIANS 
outside gills disappear. Still later, as lungs begin to develop, 
the tadpoles come to the surface for air so that for a time they 
are getting the oxygen both from the air and the water. 
(See Figure 79.) 
About this time the hind legs begin to appear, the tail 
shortens and, soon after, the front feet may be seen. By 
the first of July the tail has entirely disappeared and the 
small toad begins to hop around on the bank, having the 
form, attitude, and habits of the toad as we see him in the 
garden. From the bank they begin to travel away from the 
water and scatter over the country in all directions. After 
Figure 80. — Different Stages in the Life History of the Toad. 
a rain or during a shower, thousands of them are sometimes 
found hopping along a ravine or highway. Here they are 
run over by man and beast and fed upon by crows and other 
enemies. Of the hundreds that leave the pond but very 
few ever live to be a year old. Since toads feed on a great 
variety of harmful insects they are recognized as beneficial 
animals. Although slow moving, the toad is able to feed 
upon many flying insects which he strikes with his quick 
moving tongue, as they rest on plants or crawl over the 
ground. 
The study of the changes through which the egg of the 
frog grows into a tadpole and then into a frog tells us much 
about the way frogs may have developed from fishes. The 
