44 THE UNIVERSITY SCIENCE BULLETIN. 



Measurements of lower teeth in millimeters. 



Tooth. Height. Length. Width. 



Pma 58 30 17 



Pm4 65 29 17 



Ml 56 25.5 15 



The enamel of these lower teeth shows little plication of the 

 enamel, and in that respect they are different from those which 

 are in this paper identified as Equus leidiji. These teeth are some- 

 what smaller than might be expected; however, they are all, and 

 especially the molar, worn down to where the length is somewhat 

 diminished. 



Equus leidyi Hay. 



In the collection there is a part of the left maxilla, which con- 

 tains the last premolar and all the molars (pi. II, fig. 2). The 

 specimen was found in the Meade gravels, at the head of Bluff 

 creek, in Clark county. It was regarded by Doctor Cragin as 

 Equus curvidens Owen; but the teeth of that South American 

 species have the enamel less complicated and the styles stand 

 out less prominently from the outer face. 



The teeth of the Bluff creek specimen are those of a horse 

 probably hardly four years old. The last premolar had been but 

 slightly abraded; the hindermost molar had not yet been cut. 

 The first and second molars are only moderately worn. 



The maxilla reaches the midline, thus presenting one-half of 

 the width of the palate, which had, between the first molars, a 

 width of 75 mm. The posterior palatine foramen opened opposite 

 the front half of the second molar. The maxillary ridge contin- 

 ued forward to the middle of the last premolar. 



The last premolar is slightly curved; the molars are much 

 curved. As one follows th^m upward from the grinding surface 

 they bend both backward and inward (pi. II, figs. 3, 4). The 

 following measurements are afforded. The length and the 

 width are taken somewhat above the grinding surface. The 

 dimensions of the last molar are of less importance than those of 

 the other teeth. 



Measurements of the cheek-teeth in millimeters. 



Tooth. Height. Length. Width. Protocone. 



Pm3 92 28 29 12 



Ml 90 27 27 12 



M2 97 27 26 12 



M3 70 26 24 



