1-24 



]'i:(h:li:ms or luui) life. 



Vertebrate Animals. 



Are they warm or cold 



blooded ? 

 Have they a iiiotamorphosis 



(or change of shape) ? 

 How do they breathe ? 

 Do they lay eggs ? 

 How are they covered ? 

 What sort of limbs have 



they? 



Fishes 



Hatrocliiuns 



Reptiles 



Binlh 



Maiiunals 



By writing an answer to each question and reading the 

 columns do^vnward, he will make a definition of each class of 

 creatures. Try this yourself and see how well you succeed. 

 At least you will lind yourself giving definitions very differ- 

 ent from those you would have given a few minutes before. I 

 suspect that had you been asked what a fish is, you would 

 have said, " A fish is a swimming creature," and you would 

 have defined a bird as " a creature that flies." Then what a 

 tangle we should have been in 1 There are birds that swim 

 nearly all the time, and mammals that cannot live out of 

 water, reptiles that swim as w^ell as fishes, and fishes that 

 come out on dry land. And there are lizards that fly, and 

 reptiles that fly, and mammals that fly, not perhaps as well 

 as most birds, but much better than some birds, which do not 



fly at all. 



You see now the difference between a scientific definition 

 and an unscientific one. The scientific definition refers to one 

 thing or class of things and to nothing else. It is accurate. 

 You have seen how scientific definitions are made; indeed, 



