96 MACHAIRODUS. 
The head of this species is about half the size of that of Machatrodus neogaus, 
and indicates an animal about one-fifth smaller than the American Panther, Felis 
concolor. 
Lateral View—(Pl. XVIII. 1.) In the side view, the upper outline of the skull 
is more convex antero-posteriorly than in the species of Machatrodus just 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 Fe/is, 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 tuberosity. 
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 Félis, and anterior again to this the convexity of the 
canine alveolus commences. 
In the specimen, the upper carnassial tooth is placed far 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 are much less 
