THE LIFE OF MAMMALS 
developed among dogs and bears, which have little other means 
of seizing an animal, whereas the cat has the efficient aid of its 
claws. But after a predatory animal has killed its victim the 
tough flesh must be cut into pieces small enough to be swallowed, 
and an instrument well suited to this has been gained in the 
alteration of the elsewhere blunt fourth premolar in the upper 
jaw, and the first 
sex the Pai Kz : molar in the lower 
A sft > Be a c . 
7 ae y et ia >: yo l jaw, into thin, sharp, 
A ae as ao 3 * jf’. three-pointed fangs, 
oi Ag oO NS Mae shutting down past 
at »s aa PE AI ea ae 
Sy 7 $ one another like a 
pair of scissor blades. 
These are called the 
‘‘sectorial” or “car- 
nassial” teeth, and they are often larger and more prominent 
than either the knifelike or conical ones in front of them, or 
the robust molars behind them, whose crowns are studded with 
tubercles, definite in number and arrangement. 
The classification of the Carnivora has been a puzzling task, 
on account of the “generalized” character of many of the 
fossil species, and the constant disclosure of facts 
disconcerting to previous conclusions; but the pre- 
vailing view now is that the order should be divided into 
families arranged as follows : — 
DENTITION OF A CARNIVORE (FOX), 
¢, canine teeth; s, sectorial teeth, or carnassials. 
Families. 
TI. Lanp Carnivora — FISSIPEDIA 
Cats (Felide) ‘ wn ie : Cosmopolitan. 
Saber-Tooths (Nimravide) F ‘ 2, oR Extinct. 
Civets (Viverride) i) AO Old World. 
Hyenas, etc. (Hyzenide) ; doy Old World. 
Weasels, Badgers, etc. (Mustelide). . : Cosmopolitan. 
Dogs (Canide) ue he . . . Cosmopolitan. 
Bears (Ursidz) : api, 8 é a Cosmopolitan. 
Raccoons (Procyonide). . . bey Ae “whos cae ATHEHIEA: 
84 
