64 ANIMALS OF THE PAST 



scribed and one probably more like a whale 

 than Zeuglodon himself, whose exact relation- 

 ships are a little uncertain, as may be imagined 

 from what was said of its structure. Mixed 

 with the bones of Zeuglodon was the shell of 

 a turtle, nearly three feet long, and part of the 

 backbone of a great water-snake that must 

 have been twenty-five feet long, both previ- 

 ously quite unknown. One more curious 

 thing about Zeuglodon bones remains to be 

 told, and then we are done with him ; ordina- 

 rily a fossil bone will break indifferently in any 

 direction, but the bones of Zeuglodon are built, 

 like an onion, of concentric layers, and these 

 have a great tendency to peel off during the 

 preparation of a specimen. 



And now, as the wheels of time and change 

 rolled slowly on, sharks again came uppermost, 

 and the warmer Eocene and Miocene oceans 

 appear to have fairly teemed with these sea 

 wolves. There were small sharks with slender 

 teeth for catching little fishes, there were 

 larger sharks with saw-like teeth for cutting 

 slices out of larger fishes, and there were sharks 



