96 MACIIAIRODUS. 



The head of this species is about half the size of that of Machairodus neogaus, 

 and indicates an animal about one-fifth smaller than the American Panther, Felis 

 concolor. 



Lateral View. — (PI. XVIII. 1.) In the side view, the upper outline of the skull 

 is more convex antero-posteriorly than in the species oi Machairodus ]uiit mentioned 

 or the Panther, from the greater elevation of the forehead above the orbits posteriorly. 



The ossa nasi are not prominent above the border of the upper extremity of the 

 OS maxillare superius, as in Felis, but are concealed from view laterally, and the 

 anterior slope of the head is more uniform in its descent, or is less arched than in 

 this genus. 



The temporal fossa relatively to that of Felis is shorter, of greater breadth, and 

 much greater depth. The anterior surface of the zygomatic root inclines at an 

 angle of about 50°, instead of being nearly horizontal, as in Felis. The temporal 

 surface generally disposes to be much more rapidly convergent towards its exit 

 inferiorly than in the latter, and indeed the whole arrangement of the temporal 

 fossa is such as to have given a much less oblique course to the fibres of the 

 temporal muscle. 



The entrance to the meatus auditorius is not a broad archway, as in Felis, but is 

 a relatively deep narrow arch, apparently resulting from a modification of that in 

 the latter genus, produced by the root of the zygomatic process being depressed 

 downward and backward. The meatus is bounded posteriorly by a relatively very 

 robust and distinct mastoid process, which is directed downward and forward, and 

 has a broad rough apex for muscular attachment. The posterior surface of the 

 process curves upward and backward, and its base abuts against the paramastoid 

 process, which is a short, thick, roughened tubei-osity. 



The form, relative size, and direction of the orbit are the same as in Felis; being 

 ovoid, with the narrower part above. It is an inch and four lines in vertical 

 diameter, and has the plane of its entrance inclined at an angle of about 50°; 

 presenting outward, forward, and upward. 



The infra-orbitar foramen is vertically oval, and not only relatively but absolutely 

 very much larger than that of the Panther. It is about half an inch in vertical 

 diameter and five lines transversely, and is situated internal to the position of the 

 orbit, with more than half its extent placed above the line of the lower margin of 

 the latter. 



Above the foramen, just in advance of the orbital margin, the surface is more 

 definitely concave than in Felis, and anterior again to this the convexity of the 

 canine alveolus commences. 



In the specimen, the upper carnassial tooth is placed fiir external to the tooth in 

 advance, but this relation of position appears to be the result of a dislocation inward 

 of the latter, and it is most probable that in the natural condition the upper molars 

 were arranged in an oblique line convergent forward and upward, as in Felis. 



The anterior portion of the external alveolar surface is transversely concave, but 



vertically is very strongly convex in comparison with what it is in the latter genus. 



Superior View. — (XVIII. 2.) In the upper view of the skull, the temporal 



surfaces above the position of the roots of the zygomatic processes ai'e much less 



