DAKOTA AND NEBRASKA. 



237 



Length of temporal fossa, 



Depth " " . 



Height of face on a line with ant-orbital margin, 



Greatest breadth of forehead. 



From ant-orbital margin to lateral nasal notch, 



Breadth of face at last molar alveoli, 



Breadth of face at first molar alveoli, 



Length of upper molar series. 



Inches. 



5 



2i 



3i 



Si 



21 



3i 



2 



41 



Measurements derived from a specimen including both jaws with the teeth are as 

 follow : 



Length of the upper molar series, . 

 Length of the lower molar series, . 

 Length of the upper true molar series, 

 Length of the lower true molar series. 



Diameter of first upper molar, antero-posterior, 

 Diameter of second " " 



Diameter of third " " 



Diameter of fourth " " 



Diameter of fifth " " 



Diameter of sixth " " 



Diameter of seventh " " 



De23th of lower jaw below middle of last molar. 

 Depth of lower jaw below middle of first molar, 

 Antero-posterior diameter of second lower molar, 

 Antero-posterior diameter of third " " 



Antero-posterior diameter of fourth " " 

 Antero-posterior diameter of fifth " " 



Antero-posterior diameter of sixth " " 



Antero-posterior diameter of seventh " " 



Of other bones of Eyracodon nebrascensis, a number of fraginents are preserved in 

 the various collections of Mauvaises Terres fossils I have had the opportunity of ex- 

 amining. In general, they resemble in form the corresponding parts in the Lidian 

 Rldnoceros, and the}' present some variation in size. 



An atlas, apparently referable to HyracoJon, differs from that of the animal just 

 named in being proportionately longer, and apparently in having shorter transverse 

 processes, which are pierced fore and aft for the passage of the vertebral blood-vessels. 



• 





Lines. 



57 



• 



• • 



54 



■ 



• • « 



29 



• 



• • « 



29 



Lines. 



6; 



transverse, 



Lines 



6 



7i 



(( 



9i 



8i 



(( 



lOJ 



9v 



(( 



IIJ 



9J 



((' 



11 



11 



11 



lU 



9J 



li 



lOi 





• • 



. 20 





• 



. 14 





• • 



7 





, . 



8* 





• • 



. U 





• • 



8 





. 



. 10 





■ • 



. lOJ 



