54 



University of California Publications. [Geology 



Mr. Leander S. Davis, whose efficient serviees as guide and col- 

 lector I take pleasure in recognizing in this connection. 



Cranium. — The size of the skull places this form among the 

 larger and more powerful John Day carnivores. The cranium 

 is characterized particularly by the very high and thin sagittal 

 crest, which is so strongly elevated that the highest point on the 

 skull is thrown extraordinarily far back. The brain case is small 

 and the thin crest rises quite abruptly above it. The parietal 

 foramina are situated low down on the base of the crest, but on 

 the left side there is an additional foramen higher up on the side. 

 The occiput is high and narrow, its width a little below the 

 middle being less than that near the upper end. The lower por- 

 tion is evenly rounded but not keeled, the upper portion is gently 

 concave. A faint median keel and two lateral ones arise near the 

 upper end, but no strong or persistent keel is present on the occi- 

 put. The zygomatic arches are widely spread. The root of the 

 zygomatic process of the temporal is not lowered below the level 

 of the basisphenoid as in Hoplophoneus. The glenoid fossa is in 

 nearly the same plane with the inferior surface of the basisphe- 

 noid, but is not below it, and there is no apparent tendency to- 

 ward the development of an inferior pedicle for the support of 

 the jaws such as is seen in the typical sabre-tooths. The posttym- 

 panic process extends below the plane of the paroccipital process, 

 bu1 is not more strongly produced inferiorly or more closely ap- 

 proximated to the postglenoid than in Pogonodon brachyops. 



The facial region is flattened and somewhat depressed imme- 

 diately in front of the orbits, and the nasals are not prominent. 

 The superior extensions of the premaxillaries reach backward a 

 considerable distance, but do not meet the frontals. The nasals 

 extend backward to a point a little behind the narrowest space 

 between the superior margins of the orbits and considerably pos- 

 terior to the highest point of the mamillaries. Immediately be- 

 hind the union of the fronto-maxillary and fronta-nasal sutures 

 the nasals are slightly widened. The postorbital processes are 

 prominent and the frontal region is relatively wide. The fronto- 

 maxillary suture extends upward from the border of the orbit 

 and then turns forward nearly horizontally before bending down- 

 ward to the nasal suture, leaving the frontal with a very small 



