CARNARIA. 93 
It is easy to conceive that those genera which have the 
fewest false molars, and whose jaws are the shortest, are those 
best adapted for biting. 
It is upon these differences that the genera can be most 
surely established. 
It is necessary, however, that the consideration of the hind 
foot should be added to them. 
Several genera, like those of the two preceding families, in 
walking, or when they stand erect, place the whole sole of the 
foot on the ground, a fact proved by the total want of hair on 
that part of it. 
Others, and by far the greater number, walk on the ends of 
the toes, by raising up the tarsus.. They are much swifter, 
and to this first difference are added many others of habits, 
and even of internal conformation. In both the clavicle is a 
mere bony rudiment suspended in the muscles. The 
PLANTIGRADA 
Form this first tribe, in which the whole sole of the foot is 
placed on the ground in walking, a circumstance which gives 
them a greater facility in standing vertically upon their hinder 
feet. They partake of the slowness and nocturnal life of the 
Insectivora, and, like them, have no cecum: most of those 
that inhabit cold countries pass the winter in a state of torpor. 
They all have five toes to each foot. 
Ursus, Lin. 
Bears have three large molars on each side(1) in each jaw, alto- 
gether tuberculous, and of which the posterior upper, and anterior 
lower are the longest. They are preceded by a tooth a little more 
trenchant, which is one of the carnivorous teeth of this genus, and by 
a variable number of very small false molars, which are sometimes 
shed at a very early period. This almost frugivorous sort of denti- 
tion is the reason why, notwithstanding their great strength, shew 
seldom eat flesh unless from necessity. 
They are large stout-bodied animals, with thick limbs, and a very 
(1) We shall hereafter omit the repetition of the words ‘‘ on each side,” &c., it 
being understood that we speak of the molars on one side only, those of the other 
being the same. 
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