CAi^iD^. 897 



A second specimen, which is from the same locality as the last, in 

 Eastern Colorado, consists of the skull anterior to the orbits and the poste- 

 rior nares, lacking the superior walls. The teeth are all pi-esent, excepting 

 one first premolar and five incisors. The form is short and wide, the malar 

 bones much expanded and the muzzle narrowed. The size of the teeth is 

 about that of the Temnocyon coryphceus, but the posteriorly-expanded out- 

 line is like that of the T. josephi. The sectorial is a little smaller than that 

 of the A. vetus from the same locality ; but the principal diff'erence becomes 

 apparent on comparing the tubercular molars. The second of the A. harts- 

 Jiornianus has not more than half the surface area of that of the A. vetus. 



The external incisor is short and rather stout ; the canines are long, 

 curved, and acute, and with convex inner side ; the inner cutting ridge is 

 faint, the posterior moderately distinct. They are much more slender than 

 in the T. coryphaeus. There is a diastema behind the canine equal to the 

 long diameter of its alveolus. The first premolar has a long base and a 

 short anteriorly-placed apex ; it is followed by u space equal to its long 

 diameter. The second premolar is low and is prolonged backwards at the 

 base ; it is followed by a short space. The second premolar is more sym- 

 metrical, but has no distinct basal tubercles ; there is a faint trace of a 

 posterior median tubercle. This tooth will distinguish the species from 

 Temnocyon coryphceus if other parts are wanting The sectorial is small for 

 the size x)f the tuberculars ; its inner anterior tubercle is well developed. 

 The first tubercular has a well-developed external basal cingulum. The 

 two external cusps are low; the space between them and the inner border 

 is nearly equally divided by a low V- shaped ridge. This character will dis- 

 tinguish this tooth from those of Temnocyon altigenis and T. wallovianns. The 

 second tubercular is much smaller and stands much within the external 

 border of the sectorial. Its external border is very oblique, more so than 

 that of the first. It resembles the latter in details, the points being less 

 pronounced ; and the external cingulum is obsolete. The third tubercular 

 is opposite the inner half of the second, and its surface area is very small, 

 rather less than that of the base of the first premolar. It is supported on a 

 projection of the maxillary bone, which is separated from the base of the 

 pterygoid process of the palatine by a deep notch. The posterior nareal 

 57 c 



