33 lines. 



36 



lines. 



39 lines, 



14 " 



16^ 





16J " 



7 " 



7 





7 " 



lOJ " 



14 





14 " 



13 " 



14 





14 " 



6 " 



6 





bi " 



DAKOTA AND NEBRASKA, 29 



C. ssevus. C. occid. 



Space occupied by the back five molars, . 

 Depth of jaw below sectorial molar, 

 Thickness " " 



Depth below the third premolar, 

 Antero-posterior diameter of sectorial molar, 

 Transverse " " " 



Canis temeraeius. 



An extinct species of Wolf, or perhaps Fox, for which the above name has been 

 proposed, is supposed to be indicated by two small fragments of jaws obtained by Dr. 

 Hayden from the Niobrara sands. 



One of the fragments consists of a portion of the upper jaw containing the sectorial 

 molar and the succeeding tubercular molar, both mutilated. The other fragment, 

 represented in figure 12, plate I, consists of a portion of the lower jaw containing 

 the sectorial molar. The specimens are intermediate in size with the corresponding 

 portions of the jaws of the Prairie Wolf, Canis latrans, and the Red Fox, Canis 

 fulvus, and they accord with them in form and proportions. 



The measurements of the specimens, in comparison with corresponding portions of 

 the latter species, are as follows: 



C. tern's. C. latrans. C. fulvus. 

 Space occupied by the upper sectorial and first 



tubercular molars, . . . .12 lines. 14 lines. 10^ lines. 



Antero-posterior diameter of the upper sectorial 



molar, . . . . . 7* " 9 " 6j " 



Transverse diameter of first upper tubercular molar, 7 " 8 " 6 " 



Depth of lower jaw at sectorial molar, . . 8 " 9 " 7 " 



Antero-posterior diameter of sectorial molar, . 7i " 10 " 7 " 



Canis vafer. 



A doubtfully extinct species of Fox, distinguished by the above name, was 

 supposed to be indicated by the greater portion of both halves of a lower jaw, 

 obtained by Dr. Hayden from the Niobrara sands, with other fossils. The better half 

 of the specimen is represented in figure 11, plate I, and contains all the molar teeth 

 except the first one, which has been introduced in the figure from the other side of 

 the jaw. Notwithstanding its associations, it approaches so closely in character the 

 corresponding portion of the lower jaw of the existing Swift Fox, Canis velox, that it 

 may reasonably be supposed to belong to this animal. The ascending portion of the 



