CHAPTER IV 



REPTILES AND AMPHIBIANS 



Principle of animal classification. The general properties of animals 

 explained by heredity and adaptation. Darwinian justification 

 of classification. Reptiles and amphibia of former ages. Earlier 

 periods of the earth. How and why the earth has changed up to 

 the present. How the remains of earlier animals have been 

 preserved. Gaps in the remains of extinct animals. Primitive 

 man. Conflicts of extinct animals. Why the gigantic forms of 

 earlier ages became extinct. The death of species. Trans- 

 formation of species. Why ancient species have been 

 preserved. Why there are still animals of the simplest type. 

 Predominance of a species of animal. Predominance of 

 man. Any variation is possible. Origin of flying animals. 

 Life of our reptiles. Prey. The creeping of serpents. Re- 

 generation, the power to re-form lost members. Its origin by 

 natural selection. Frog-spawn. The skin of amphibia. Repellent 

 and warning colours on nauseous and poisonous animals. 



THE man who devotes himself to the study of living 

 organisms is overpowered by the inconceivable variety 

 of their forms. He would have to despair of ever 

 obtaining a grasp of the world of living things if he 

 had not in language a means of ranging a vast number 

 of forms under one convenient name. With one word 

 he can designate countless numbers of animals, each of 

 which is different from the other, by ignoring the 

 differences between them and fastening on what is 

 common to all the individuals. The word "fox" 

 enables us to grasp a countless number of animals, by 

 representing to us the common element of them all. 



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