120 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



ment of paleontology pm* and m^ are figured (pi. 7, figs. 9-12). 

 They have suffered only a moderate degree of wear. The measure- 

 ments obtained from these teeth are as follows : 



MEASUREMENTS OF UPPER PREMOLARS AND MOLARS. 



Height. 



Length. 



Width of 

 protocone. 



Third premolar.. 

 Fourth premolar. 



First molar 



Second molar 



33 



31.5 

 30 

 29 



32 

 32 



30.5 

 29.5 



15 



15.5 

 15.5 

 16.5 



The parastyles and mesostyles of these teeth are unusually broad. 

 The width of the parastyle of the third premolar is nearly 8 mm. ; 

 that of the mesostyle, 8.5 mm. The widths of the styles of the fourth 

 premolar are only slightl}?^ less. The parastyles are traversed by a 

 well-defined narrow channel. The styles of the molars are about .5 

 mm. wide at the grinding surface, but they broaden somewhat 

 toward the base. The second molar has the styles obscurely chan- 

 neled. These styles are broader and more distinctly grooved length- 

 wise than are those of a very large domestic horse at hand. 



The measurements show that the protocones do not vary much in 

 width in the different teeth; also they diminish little or not at all in 

 width toward the base of the tooth. The post-protoconal valley is 

 directed so that its axis continued would meet the front of the tooth 

 at the middle of the width. The direction is the same in premolars 

 and molars. In E. cabaUus the axis of the valley of the molars is 

 inclined toward the inner face of the tooth. At the head of the val- 

 ley of the premolars of E. holviesi there is an intiection of the 

 enamel ; in the molars this is minute or wanting. The enamel of the 

 fossettes is relatively simple, more so than in Equus cabaUus. In 

 the premolars there is a pretty deep notch or loop in both the front 

 and the rear walls of both fossettes. In the front wall of the post- 

 fossette, outside of the large loop, there are one or two small inflec- 

 tions of the enamel. Facing the head of the post-protoconal valley is 

 a deep somewhat M-like inlet into the fossette. In the molars the 

 notch in the front of the prefossette is small or wanting. The cornua 

 of the fossettes are broad. According to Professor Holmes's ac- 

 count already referred to (his page 241) these teeth were regarded 

 as those of the domestic horse. They were found, however, at a 

 depth of 7 feet or more and closely associated with teeth of ap- 

 parently ElepJias imperator. These teeth are too large to have be- 

 longed to the domestic horse ; the enamel is of too simple a pattern, 

 the styles are too broad, and there are other differences. The size of 

 the teeth is not different from the teeth of E. scotti (probably the 



