78 NATURE STUDY. 



with red, while the shell underneath is yellow. These tur- 

 tles are not so easily captured as the wood turtles, for they 

 are rather timid and often slip into the water when ap- 

 proached, but with patience and ingenuity they can be 

 outwitted at last and one secured for examination. 



It is best to watch them for a time, observing their 

 ways, before trying to catcfi them. Observ^e how they 

 walk and how they swim. Of course they use their feet 

 for both purposes, and they also sometimes use a fore foot 

 to hold down their food while eating. It will be rare good 

 fortune to find a turtle at a meal and see him hold his food, 

 sometimes with one fore foot, sometimes with the other, 

 but never with both at once, as cats and dogs often do. 



Turtles can remain under water for a considerable time, 

 for they are cold-blooded creatures and do not use up the 

 air in their lungs so rapidly as warm-blooded animals do. 

 Besides, turtles swallow air instead of breathing it, their 

 lungs being little else than large sacs, which can be filled 

 with air, like a bladder or toy balloon. Before diving un- 

 der water, a turtle swallows a bagfuU of air, and can re- 

 main until it has all been used, when he must come to the 

 surface and swallow another bagfull. Sometime, if we dis- 

 sect, or cut up and examine a turtle carefully, we shall 

 find these bag-like lungs very curious and interesting, but 

 for the present we are to study the outside of the animal. 



After watching them for awhile, contrive to catch one. 

 Notice how he can draw his head, feet and tail within his 

 shell. Try to find whether he always draws his tail in on 

 the same side of his box house. Experiment with the 

 same turtle over and over ; then sometime try other turtles 

 in the same way, and find out for yourself whether turtles 

 vary in this matter of hiding away their tails. This is more 

 important than you can imagine. If all the animals and 

 plants of the same sort were always the same, there would 

 never be any change in the living world. 



