522 



PROCEEDINGS OF TEE NATIONAL MUSEUM. 



vol. 48. 



The second and third premolars of the Jersey had not been cut, 

 and the first two measurements of the third column start with the 

 front of the corresponding milk molar. In the case of the second 

 molar of Bison oison (Xo. 14099, Amer. Mus. Xat. Hist.) the height 

 and the greatest width can not be determined without cutting into 

 the bone. The heights of the teeth are given in order to indicate 

 approximately the amount of wear. As the teeth are worn down 

 the fore-and-aft length of the crown diminishes, while the width 

 increases. It is to be noted that the teeth of the Jersey cow are 

 less worn down than either of the others. Were we to measure the 

 length of the crown of the jersey at the same level as those of the 

 fossil, the former would show a length at least a milli- 

 meter less than they do. TVTiere possible, the width of 

 the teeth as given is that at the base, where greatest. 



It is necessary now to compare the teeth of the fossil 

 with those of the jersey and of the bison. The teeth of 

 the fossil (pi. 30, figs. 3, 4; text-fig. 1) are somewhat 

 injured, but not to a serious extent. A little enamel is 

 split off from the outer and the inner styles at the 

 rear of the fourth premolars. A part of the hinder 

 inner column (entoconid) is broken away, also a very 

 little of the summit of the anterior outer column (pro- 

 toconid) of the second molars; likewise a sliver from 

 the hinder inner style of the same tooth. All of the 

 cement has been dissolved off the teeth and the dentine 

 is considerably decayed. The enamel of the teeth is 

 apparently more wrinkled than in most specimens of 

 the two species with which it is here compared. 



In the fourth premolar the excavation, or infold, in 

 the outer face, in front of the hinder style, is much nar- 

 rower and more sharply denned than in the specimens 

 of B. oison examined. In the existing bison there are 

 usually two infoldings of the enamel of the hinder half of the inner 

 face of the tooth and in front of these a narrower excavation or 

 channel. Sometimes the hinder infold is divided so as to cut off 

 a circular pit in the hinder part of the tooth. The anterior infold 

 referred to is usually directed inward and often inward and back- 

 ward. In the fourth premolar of B. sylvestris there is a circular 

 pit in the hinder part of the tooth, as seen in the figure. The 

 enamel of the inner face is directed forward and outward to near 

 the point of the tooth, then abruptly inward, then again outward 

 and forward, and finally again inward. There is thus formed 

 a great excavation in the inner face of the tooth, and in front of 



Fig. 1.— Lower 

 molabs of Bi- 

 son STLYES- 

 TEIS. X 1. 



