Vol. 5] 



Mcrriam. — John Day Carnivore/,. 



39 



lui •■us and Nimravus. As in Archaelurus debilis, there are four 

 superior premolars. The upper canine is slightly shorter and 

 appears to show a little more curvature than in Nimravus, but 

 in other characters it differs greatly from Archaelurus as de- 

 scribed, and in these particulars resembles Nimravus. The 

 posterior side instead of being smooth-edged is strongly com- 

 pressed and has a sharply serrated margin. As in Nimravus, the 

 anterior side is broad, and is slightly concave toward the inner 



Fig. 15. Archaelurus debilis major. No. 1681. Middle John Day, Logan 

 Butte, Crook County, Oregon. X %. 



angle. The outer anterior portion is rounded. The inner ante- 

 rior angle is acute, and is noticeably serrated toward the base of 

 the tooth. In this last character it is even more specialized than 

 the corresponding portion of this tooth as described for N. gom- 

 phodus. The skull in which this dentition occurs represents an 

 individual much larger than the type of A. debilis. In dimen- 

 sions it is nearest to the type of N. gomphodus, the largest de- 

 scribed form referred to either of these genera, but it exceeds 

 this specimen in axial length by about 20 millimeters. 32 



It is difficult to determine the affinities of this form, judging 

 solely from the characteristics which appeared in the type speci- 

 mens. As the form represented by specimen No. 1681 is sepa- 

 rated from Archaelurus principally by the character of the mar- 

 gins of the superior canine, the writer has examined the type 



"Axial length of skull. Type A. debilis, 180 mm. Type N. gomphodus, 

 206 mm.; No. 1681, 225 mm. ' 



