DAKOTA AND NEBRASKA. 



Antero-posterior diameter of second upper true molar, 

 Transverse " " " 



Antero-posterior diameter of first upper true molar, 

 Transverse " " " 



Antero-posterior diameter of last upper premolar, . 

 Transverse " " " 



Antero-posterior diameter of third upper premolar, 

 Transverse " " " 



Antero-posterior diameter of second upper premolar, 

 Transverse " " " 



Antero-posterior diameter of first upper premolar. 

 Transverse " " 



Antero.posterior diameter of superior canine, 

 Transverse " " " 



Antero-posterior diameter of last lower molar. 

 Transverse " " " 



Antero-posterior diameter of second lower molar. 

 Transverse " " " 



Antero-posterior diameter of first lower molar. 

 Transverse " " " 



Antero-posterior diameter of last lower premolar. 

 Transverse " " " 



Antero-posterior diameter of second lower premolar. 

 Transverse " " " 



Antero-posterior diameter of first lower premolar, . 

 Transverse " " " 



Antei'o-posterior diameter of lower canine, . 

 Transverse " " " . 



Lin 



61 

 61 

 6 



51 

 4 

 5 



4i 

 4 

 4 

 3J 

 3 

 2 

 3 



3i 

 lU 

 41 

 7 

 5 

 5i 

 4i 

 5 



3i 

 3i 

 2i 

 3i 

 If 

 31 

 21 



Mertchtus medius. 



A second species of Merychyus, to whicli the above name is given, is founded upon 

 a fragment of a lower jaw containing the true molars, and an isolated upper last 

 molar tooth. The specimens indicate an animal one-half larger in diameter than M, 

 elegans, and intermediate in size to the Lama and Camel. 



The fragment of a lower jaw, with different views of the contained teeth, is repre- 

 sented in figures 12 — 14, plate XI. 



The first true molar has the crown nearly worn to its base. The last had not 



