REPTILES AND AMPHIBIANS 135 



conditions made this persistence possible. As a matter 

 of fact, such animals are very rare. 



We must not say that the higher animals are better 

 adapted than the lower. Higher only means, in the 

 scientific sense, more complicated, not better. The 

 bacilli that carry on the struggle of life and death with 

 man to-day show clearly how they, the lowest organisms, 

 have equipped themselves to meet the highest. 



It is said that the Jurassic period was the age of 

 reptiles. That is not correct. There were far more 

 species that were not dependent on the giant lizards 

 than species that were. Was the swarm of insects, or 

 were the snails, subject to them ? And if we take their 

 size and variety as a symbol of predominance, we should 

 have to say that the whales and elephants are the lords 

 of the world to-day, if not the insects, which have more 

 species than all the other classes. 



No animal species has ever dominated a period of 

 the earth's development, since there were always other 

 creatures that were overlooked by them and had no 

 relation to them. It is only since the domination of 

 man began that we speak with some justice of a king 

 of nature, as his civilisation is able to alter the funda- 

 mental conditions of animal life. But even here we 

 are only partly correct. There are still countless species 

 of animals for whom this dominion has no meaning. 



We come to the conclusion that the species that have 

 remained unchanged since remote ages have retained 

 their form because they had no enemy that compelled 

 them to change, and because within the limits of their 

 own species they grew to meet the physical conditions 



