426 G. I. Adams — Extinct Felidce of Worth America. 



Summary. 



H. jprimcevus differs from the recent Felidse and the lynx in 

 particular, in the following points : 



The skull is Machaerodont, is large in proportion to the body 

 and long anteriorly. 



The brain case is relatively much less expanded and the 

 post orbital constriction is very marked. 



The mandible has a distinct vertical anterior face and a 

 moderate flange. 



The post-tympanic is large, sub-cylindrical and shows a ten- 

 dency to approach the post-glenoid process. The zygomatic 

 processes are drooping. 



There are distinct carotid, condyloid, post-glenoid and post- 

 parietal foramina and an alisphenoid canal. 



The dentition is IfC^PmfMi. The superior canine is very 

 long, recurved, compressed and when the mouth is closed 

 extends nearly as low as the flange of the mandible, resting in a 

 slight fossa. The superior sectorial has an anterior basal cusp 

 but no internal, the internal root supporting instead a convex 

 buttress which descends from the principal cusp. The inferior 

 sectorial has a small postero-internal cusp and a low heel. 

 The incisors are subcorneal and slightly divergent. The inferior 

 canine is not much larger than the external incisor. All the 

 teeth when unworn are denticulated or feebly crenulated and 

 the superior canines are permanently so. 



The skeleton is about the size of the lynx but more massive 

 as in the lion. ^The cervical region is rather long and the lum- 

 bar short as compared with the lynx. The tail is long as in 

 the lion. 



The humerus has a strong massive deltoid ridge, the femur 

 a third trochanter. 



The ulna and radius and the tibia are proportionately much 

 shorter than in the recent Felidse. 



The pes and manus are very short and broad. The astra- 

 galus is only slightly grooved and its tibial surface is oblique. 

 The scapho-lunar shows the line of union of its two elements. 

 The second metacarpal is nearly excluded from lateral articula- 

 tion with the magnum and the second metatarsal from lateral 

 articulation with the ecto-cuneiform. 



The unguals have heavy hoods and were retractile. 



The position of the feet was as in the modern cats. 



A comparison with Dinictis felina. 



The osteology of this species of Dinictis, as has already been 

 stated, has been described by Scott. In addition to the material 



