Vol. 5] 



Mcrriam. — John Day Carnivora. 



41 



As in the crania described above, the mandibles in the Univer- 

 sity collections all show more or less mixing of characters. A 

 large specimen (No. 1679, text-figure 16) exceeds the type of A. 



Fig. 16. Archaelurus debilis major. No. 1679. Middle John Day, Blue 

 Basin, Turtle Cove, John Day Valley, Oregon. X %. 



debilis in size by about 30 per cent. Its dimensions are in general 

 near those of the type of N. gomphodus, but it is even larger than 

 that form, and apparently represents the largest known individ- 

 ual of this group. The exostosis is intermediate in size between 

 the slight thickening in N. gomphodus and the greatly inflated 

 alveolar border of A. debilis. The massateric region is similar 

 to that of Archaelurus, but the mandible is relatively higher be- 

 low the diastema than in the type specimen. The posterior angle 

 of the canine is denticulate, as in Nimravus. P 2 is double-rooted 

 instead of single-rooted as described for Archaelurus by Cope, 

 but a reexamination of the type shows that it is two-rooted there 

 also. P., possesses a small anterior basal tubercle as in Archae- 

 lurus. 



In another specimen (No. 1680), representing the median 

 portion of the jaw, the inferior canine,, and several lumbar verte- 

 brae, the dimensions are intermediate between those of A. debilis 

 and the large specimen described above. The exostosis is little if 

 any larger than in Nimravus, and the canine shows posterior ser- 

 ration, but the massateric region is apparently as in Archaelurus. 

 The height of the jaw seems to be relatively less than in the 



