PROBLEM I. The Kinds of Annuals of the Earth 



3T 



Fig. 42 A green frog can jinnp fifty times its P'lc. 43 The American toad cannot jump as far 

 length. What structures make this possible}' as the frog. Can you tell why}' ( Schneider and 



(AMERICAN MUSEUM OF NATURAL HISTORY) SCHWARTZ) 



part on land. While in the water stage 

 thev obtain air by means of gills; in the 

 land stage they use lungs for breathing. 

 There are a few species which do not 

 develop lungs at any stage and never 

 leave the water; when full grown they 

 resemble a legged tadpole. 



Amphibians with tails. Biologists divide 

 the class Amphibians into two orders — 

 those with tails and those without. The 

 tailed forms, the salamanders and newts, 

 might be mistaken for lizards until one 

 discovers the moist, naked skin. They 

 are timid, harmless creatures; their feet 

 have no claws and their jaws are weak, 

 unfitted for biting. They catch insects 

 with the tongue. Some of the tailed am- 

 phibians are brightly colored; others, 

 like the hellbender, are dull and un- 

 attractive. One that many of you may 

 have found in the woods, under logs 

 or leaves, is the beautiful red newt. 



Amphibians without tails. You are 

 much more familiar with this group 

 which includes the frosts and toads. 



Thev feed on insects which they catch 

 with their long, slimy tongue. They 

 lay their eggs in fresh water; these hatch 

 into tadpoles which change into adults 

 as legs and lungs form. Frogs when fully 

 developed, continue to spend at least part 

 of their time resting just under the sur- 

 face of the water with eyes and nostrils 

 raised above the surface. The hind feet 

 are webbed and are equally useful for 

 swimming and jumping. Toads, on the 

 other hand, leave the pond and return 

 only in the spring to lay their eggs. Their 

 skin becomes so dry that it looks shriveled 

 and warty. The statement that you can 

 get warts from handling toads was long 

 ago proved to be untrue. Toads are not 

 only harmless to us but are a great help 

 to the gardener because they eat insects. 

 Do Exercise 9. 



CLASS - FISHES 



What is a fish? As you turned from 

 the most complex vertebrates, the mam- 



