G. I. Adams — Extinct Felidce of North America. 421 



and inserted well into the anterior border of the frontals, 

 their posterior borders being broadly rounded. The bullae are 

 seldom preserved, but judging from a cast of one they are 

 moderately expanded. 



The foramina of the skull present peculiarly primitive char- 

 acters, as has already been recognized. The condylar and 

 carotid are distinct from the foramen lacerum posterius. There 

 is a post glenoid foramen. The foramen ovale enters the 

 outer end of a deep transverse groove situated in the base of 

 the zygomatic process. There is an ali-sphenoid canal, the 

 posterior opening of which is in the inner portion of the above 

 mentioned groove and its anterior opening is just back of the 

 anterior lacerated foramen. The opening of the foramen 

 rotundum is concealed within the alisphenoid canal. The 

 optic foramen is in the same relation to the anterior lacerated 

 as in the cats. There is also an ethmoidal foramen present. 

 The palatal foramina need no special description. There is a 

 post-parietal foramen and sometimes two. The infra-orbital is 

 large and vertically oval. 



The mandible. — The mandible is quite characteristic of the 

 Machserodonts. Its anterior portion consists of two vertical 

 nearly plane surfaces meeting at a wide angle at the symphysis. 

 The lateral face of the mandible is separated from the anterior 

 by nearly a right angle marked by a distinct ridge, posterior to 

 which is a shallow fossa for the superior canine. At this place 

 the lower border of the mandible is produced into a moderate 

 flange on the surface of which the fossa is continued. The 

 symphysis is lower than the ramus and abuts against the flange 

 on its inner side. The ramus is long and quite straight, being 

 heaviest at the sectorial. The condyle is on a line with the 

 alveolar border and is semi-conical. The coronoid is small and 

 evenly rounded. The masseteric fossa is deep, the angle being 

 well out from the plane of the coronoid. The dental and 

 mental foramina are as in the modern cats. On the anterior 

 or symphysial surface there are two foramina on either ramus. 



Dentition. — There are three stout subconical incisors which 

 are slightly recurved and are placed in nearly a semicircle. 

 Their posterior surface, which is a little over one- third the 

 circumference of the tooth, is slightly flattened and separated 

 from the anterior by a sharp line which is slightly denticulate 

 in an unworn tooth. They increase in size outward, the 

 external being largest. The superior canines are long, com- 

 pressed and slightly recurved. They are implanted by a strong 

 fang which reaches well up to the frontal bone. Their anterior 

 and posterior cutting borders are denticulate. When the 

 mouth is closed the canines rest in the fossae of the mandible, 

 extending nearly as low as the flange. There is a small space 



Am. Jour. Soi. — Fourth Series, Yol. I, No. 6.— June, 1896. 

 28 



