DAKOTA AND NEBRASKA. 



159 



cess before and behind, extending towards the triturating border. It has nearly the 

 constitution of the crown of the corresponding tooth, or first premolar, of the Camel, 

 but is relatively shorter and wider, and has the antero-internal fold relatively better 

 developed. The worn triturating border exhibits a reniform surface of dentine, with 

 the notch outward. 



In advance of the premolars there is a hiatus, sharp bordered, but less arched or 

 straighter than in the Camel, and measuring about an inch and a quarter in 

 length. 



The first premolar, figure 17, c, holds nearly the same relative position to the other 

 teeth as in the Camel, but otherwise is different. It is directed slightly forward in 

 its course downward, and is inserted into the jaw by a pair of robust divergent fangs. 

 The crown is compressed conical, nearly as broad as long, and with the point slightly 

 curved inward. The inner and outer surfaces are defined bj' subacute borders, 

 slightly indented along their course. 



In advance of the tooth just described there is an arching hiatus about an inch in 

 length. 



The canine tooth, figure 17, h, holds the same relative position as in the Camel and 

 Lama, and presents nearly the same proportions and direction of curvature. The 

 crown, however, is relatively narrower or less compressed than in the Camel, and 

 bears more resemblance to that of an ordinary carnivorous animal. The inner and 

 outer surfaces are defined by two feeble, slightly indented ridges, occupying more the 

 internal aspect of the crown as is usual in canine teeth generally. 



In advance of the canine tooth a narrow, arched hiatus exists, about half an inch 

 in length. 



The caniniform incisor, figure 17, a, is a repetition in form and size of the tooth 

 just described, and it occupies the same relative position as in the Camel. 



The measurements of the teeth pertaining to the specimens above described are as 

 follow : 



Lines. 



Antero-posterior diameter of second premolar, . . . .6 



Antero-posterior diameter of first premolar, . . . . .4} 



Antero-posterior diameter of caniniform premolar, . . . .4 



Length of crown of caniniform premolar, . . . . -. 4J 



Length of crown of canine tooth, . . . . . .9 



Antero-posterior diameter of do. . . . . . -4^ 



Transverse diameter of do. . . . . . .4 



Length of crown of caniniform incisor, . . . . .9 



Antero-posterior diameter of do. . . . . . 4J 



Transverse diameter of do. . . • . . 4i 



