68 THE BRONTOSAUR AND ITS COUSINS 



now the swimming reptiles, some of which had, as 

 I said, swift fish-like paddles, eyes fifteen inches in 

 diameter, and crocodile-like jaws adorned with about 

 two hundred teeth. We do not wonder that the 

 geological chronicle shows a rapid improvement of 

 the fishes — especially of their power of getting away — 

 but we will not go into the details. 



Every section of living nature had new terrors and 

 new enemies. There was, as yet, no social life, except 

 among such animals as corals and sponges and polyps, 

 which have no intelligence (and most probably no 

 consciousness whatever) to profit by it. Carnage, and 

 changes of land and water, were the great stimulants. 

 Besides the sharks and Ichthyosaurs, for instance, 

 there now appeared in the ocean the king of the 

 shell-fish family, the Ammonite. He lived in a great 

 curved shell, like a coiled snail's shell, which was 

 sometimes three or four feet in diameter. At the 

 opening of this he watched for his prey, with great 

 eyes and a huge expectant mouth. He greatly helped 

 the world of small invertebrate animals of the sea to 

 move on to a higher level. 



But we will keep to the broad lines and general 

 principles of the subject. This Mesozoic Era was, as 

 I said, a period of reaction between two revolutions. 

 With the second revolution we open, not exactly the 

 modern period, but the period of the ancestors of our 

 modern types, and we move in a world that is less 

 strange. The revolution was, of course, another 



