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CLASS MAMMALIA. 



Family Coryphodontid^. — The upper premolars (fig. 1258) are 

 simpler than the true molars, and there are frequently two V-shaped 

 ridges on the latter. The type genus Coryphodon was originally 

 founded by Sir R. Owen upon a lower molar from the London 

 Clay ; other teeth were subsequently found in the Lower Eocene of 



the Continent, but it was reserved for the discoveries in the homolo- 

 gous strata of North America to indicate the full structure of this 



curious genus. The dentition is I. -, C. -, . 



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structure of the upper molars, cranium, and feet is exhibited in the 

 three accompanying woodcuts (figs. 1 257-1 259.) Other forms from 

 the Eocene of America have received the names of Metalophcdcn 



- , M. - ; and the 

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