Early Birds and Mammals 



recent water -fowl have done their 

 best to develop teeth, for the beak 

 of the mergansers is furnished with 

 a series of sharp tooth-like points, 

 and there are sharp spines on the 

 tongue as well. These, however, are 

 developed on the horny covering of 

 the beak, and thus belong in the 

 same category as hair and feathers. 

 A Cretaceous bii'd from England, 

 Odontopteryx, presents still another 

 modification, the margins of the bony 

 jaws themselves being produced into 

 sharp points to serve as teeth. 



Nearly all our known Cretaceous 

 birds have been found in the chalk 

 cliffs of Gove and Logan Counties, 



Jaw, vertebra, and single tooth of Hesperornis re- 

 galis. The vertebra and jaw are smaller than the 

 originals, and the tooth is twice natural size. 



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