CHAP. 60.—THE MOUTH; THE LIPS; THE CHIN; AND THE
JAW-BONE.
It is from the " labia," or lips, that the Brocchi [Note] have received the surname of Labeo. All animals that are viviparous
have a mouth that is either well-formed, or harshly defined,
as the case may be. Instead of lips and mouth, the birds
have a beak that is horny and sharp at the end. With birds
that live by rapine, the beak is hooked inwards, but with those
which gather and peck only, it is straight: those animals,
again, which root up grass or puddle in the mud, have the
muzzle broad, like swine. The beasts of burden employ the
mouth in place of hands in gathering their food, while those
which live by rapine and slaughter have it wider than the
rest. No animal, with the exception of man, has either chin
or cheek-bones. The crocodile is the only animal that has the
upper jaw-bone [Note] moveable; among the land quadrupeds it is
the same as with other animals, except that they can move it
obliquely.