LIST OF FIGURES IN TEXT. 



Archelon ischyros Wieland. Left epiplastron. Inner (superior) view 

 Aspidonectes spinifer. Nether (ectal) view of plastron 

 Dermochelys coriacea. Plastron with ectal and ental view of nuchal 

 Aspidonectes spinifer. Ental view of nuchal, and the entoplastron of 



Archelon ischyros . 

 Osteopygis gibbi Wieland. Plastral view. Primitive semi-marine 



turtle from New Jersey Cretaceous 

 Testudo peragrans. Superior view of skull 

 " " Inferior " " 



View of left side of skull 

 " " Lateral view of shell. 



" " Inferior view of shell. 



arenivaga. Upper side of pygal and eleventh peripheral 

 " Section along midline of pygal. 



" " Section of anterior end of eleventh peripheral 



Stylemys nebrascensis Leidy. Superior view of skull. 

 " " Inferior " " . 



" " " View of right side of skull . 



Section of the Lower Miocene of western Nebraska and eastern 

 Wyoming. ........ 



Mesoreodon megalodon. Side view of upper and lower jaws 

 " " External view of left mandible . 



Phe?iacocoelus typus. Side view of skull .... 



" " Restoration ..... 



Crown view of teeth of undetermined Canid 

 External view of right ramus of undetermined Canid. 

 Merychyus harrisonensis. Side view of skull . 



Top " "... 



Palate " " . 



Stenomylus gracilis. External view of right mandible 

 Brachypsalis simplicidens. External view of right ramus . 



" " Superior " " " 



Diceratherium niobrarense. Posterior view of skull . 



' ' cooki. Top view of skull .... 



Palate " " . 



9 

 10 



21 

 15 



15 

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 17 

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 20 

 20 



23 

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34 

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 48 



