524 CARNIVORA 
premolars, and the lower carnassial may retain its inner cusp. 
-Elurictis, of the French Phosphorites, with j =— m a together 
with several American Miocene genera, such as Vimravus (p 3, 
m 4), drchelurus (p aap m 4), Pogonodon (p 3, m +), and Hoplo- 
phoneus (p cS, m 1), approach more closely to the modern Cats, 
although many or all of them retain the alisphenoid canal, and have 
not yet developed the anterior lobe to the upper carnassial, or lost 
the talon to the lower one. Hoplophoneus has a descending flange 
to the mandible ; and its scapholunar bone has a line indicating its 
dual origin; while the femur still retains the third trochanter, 
of which all traces are lost in the modern Cats. 
On the other hand, some of the extinct Felide show a most 
remarkable tendency towards a specialisation not occurring in any 
of the surviving members of the family, viz. an enormous develop- 
ment of the upper canines, with which is usually associated an 
expansion downwards and flattening of the anterior part of the 
ramus of the lower jaw, on the outer side of which the canine lies, 
when the mouth is closed. In JJacheredus neogeus, the Sabre- 
toothed Tiger, from the caves of Brazil and also from Pleistocene 
deposits near Buenos Ayres, an animal about the size of a Tiger, 
these teeth are 7 inches in length, greatly compressed, and finely 
serrated on the trenchant anterior edges. Similar serrations are 
seen on a much fainter scale in the unworn teeth of modern Tigers. 
Many modifications of this commonly-called “ machzrodont ” type 
have been met with both in the Old and New World. In JL 
cultrudens, of the Upper Pliocene of Italy and France, the upper 
canine is long and narrow, with smooth cutting edges: the smaller 
form described as JL meganthereon being apparently the female 
of this species. I. crenatidens, of the same deposits, is distinguished 
by the shorter and broader upper canine, in which both edges are 
strongly serrated; the same feature occurring in the closely allied 
or identical IV. latidens of the English cavern-deposits. The Italian 
Pliocene form described as JV. nestianus has serrations only on the 
hinder edge of the upper canine, and the third lower premolar 
is separated by a long interval from the fourth, 1 necator, 
of the Pleistocene of South America, is remarkable as being the 
only member of the family in which the humerus has no ente- 
picondylar foramen. A very remarkable form, Eusmilus, from the 
Upper Eocene Phosphorites of Central France, differs from all other 
known Felines in having only two pairs of incisors in the lower jay, 
and a small canine separated by a very long diastema from the 
cheek-teeth, which consist only of one premolar and one sectorial 
true molar. The lower jaw is enormously expanded towards the 
symphysis to protect the large upper canines. This animal then, 
although of Eocene age, appears to form the culminating develop- 
