AMPHIBIANS 4I7 
and the body and tail; the thumb is short and terminates in a hooked 
claw. 
4. How bats rest and sleep.— Notice the. toes on the hind feet; 
how the bat hangs itself up by these, head downward, and then rests. 
5. The bat on the ground. — Notice how helpless it is on the ground, 
how awkwardly and slowly it crawls. Can it take flight from the ground 
or must it crawl up on some object and then spread its wings as it drops? 
Development of Frogs and Toads 
6. The eggs. —In the spring, soon after the frogs begin their, croak- 
ing, visit their haunts in marshes or ponds and look for their eggs. They 
are as big as small peas and are embedded in transparent jelly in masses 
of varying size from a cluster of two or three eggs to a lump as large as a 
man’s fist. Take some spawn to the schoolroom and put it in a dish of 
water, — only a small number of eggs in one vessel. An old fruit jar 
will answer the purpose, but a shallow dish is better for the tadpoles 
after they are hatched. 
7. Hatching requires but a few days in warm weather. In cool 
weather it will take eight or ten days. Watch for the earliest signs of 
life in the eggs. Can you observe any movements before they are 
hatched? As soon as the tadpoles are hatched see how they swim. 
Watch for the appearance of external gills about the mouth. If you 
have a microscope put a tadpole under it and observe the flow of the 
blood through these gills. It is a wonderful sight. 
8. The tadpoles must be fed or they will not grow. Put some green 
water plants in their vessel; they will also eat cooked corn meal. It is 
difficult to keep the same specimens alive through their entire develop- 
ment. Procure some large fresh tadpoles from the pond and watch for 
their transformation into frogs by the gradual absorption of the tail 
and the development of legs. 
9. Toad’s eggs.— Toads are more easily raised than frogs. Their 
eggs are found in the same shallow water as frog’s eggs, but they are laid 
in long strings or ropes which are usually tangled up with the sticks or 
weeds at the bottom of the water. If the eggs have been freshly laid 
the string will look like a glass tube containing a row of black beads. 
Salamander eggs are similar to those of frogs and toads and found in 
the same kinds of places. 
