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 
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> ORI ae 
