2+6 THE INTERNATIONAL MONTHLY. 
Eocene on. At the present time they are distributed over south- 
ern Asia, Africa, and Madagascar. A late offshoot of this 
family is that of the hyaenas (family Hytenidce) of which the first 
distinguishable members appear in the Pliocene of the Old World, 
and, for a brief period, extended their range to North America, 
but were unable to obtain a permanent foothold here. 
The weasel family {Mustelidte) is the most numerous and 
diversified of the carnivorous groups and includes such appar- 
ently unrelated forms as the weasels, martens, skunks, badgers, 
gluttons, fishers, otters, etc. This is likewise, in all probability, 
a family of Old World origin, and descended from an ancestry 
common to the civets. They are already abundant and varied 
in the Oligocene of Europe, but remain rare in North America 
till a much later time. With all their difference of habits and 
appearance, they do not differ greatly in structure, and are all 
marked by their elongate, short faced skulls, with teeth reduced 
in number, but enlarged in size, by their long bodies, short limbs, 
and plantigrade or semi-plantigrade feet, armed with long and 
sharp claws. The three families of the civets, hyaenas, and 
weasels together form another group of closely related types. 
The cats (family Felida) are still very puzzling. They fall 
into two quite distinct lines, the true cats and the sabre-tooth 
series, which for a long period pursued parallel courses, until the 
latter became extinct in the Pliocene of the Old World and the 
Pleistocene of the New. The cats are all remarkable for the short- 
ness and breadth of the skull and for the reduction in the number of 
their teeth, but this reduction is compensated by the enlargement of 
the teeth that remain and by their conversion into a most effective 
sectorial apparatus for shearing flesh; the limbs and feet are 
very powerful, and the claws can be retracted or protruded at 
will. In the sabre-tooth cats the upper canines are drawn out 
into large, curved, scimetar-like tusks, and the lower jaw is especi- 
ally modified [to protect them from fracture. These most 
extraordinary cats make their appearance quite suddenly in the 
Oligocene of Europe and North America, although there are 
certain fragmentary Bridger fossils, which, when better known, 
