instinctive, which at least produces something like the effect of
innate sympathy, and seems to be independent of experience or
arbitrary custom. It is, in short, of man alone that we can with
strict propriety say, the countenance is an index of the mind, having
expression corresponding with each emotion.
OF TH E MUSCLES OF ANIMALS COMPARED W ITH THOSE OF MAN.
In order to see distinctly what the peculiarities of mere animal
expression are, it seems proper to reduce the muscles of expression
in animals to their classes. These muscles, as they appear in the
several quadrupeds, may be distinguished into, I. Those which raise
the lips from the teeth; 2. Those which surround the eyelids; and
3. Those which move the nostril.
1. The first of these classes, viz. the muscles which raise the lips
from the teeth, admit of a subdivision. In the carnivorous animal
the muscles of the lips are so directed as to raise the lip from the
canine teeth. In the graminivorous they are so directed as to raise
the lips from the incisores. The former I would take the liberty
of distinguishing by the name of R in g e n t e s , snarling muscles; the
latter by the name of D e p a s c e n t e s .
The snarling muscles take their origin from the margin of the
orbit of the eye, and from the upper jaw, they are inserted into that
part of the upper lip from which the whiskers grow, and which is
opposite to the canine teeth. Their sole office is to raise the upper
lip from the canine teeth", and although they are assisted in this
office by other muscles, (the masticating and zygomatic muscles)
I have ventured to distinguish them particularly as the muscles of
snarling. This action of snarling is quite peculiar to the ferocious
and carnivorous animals. The graminivorous are incapable of it,
and these muscles consequently are to be found only in the former
class, not in the latter. In the carnivorous animals there is no
perfect or regular orbicular muscle, as in man, for contracting the
lips. The lips hang loose and relaxed, unless when drawn aside by
the snarling muscles, and they fall back into this state of relaxation,
with the remission of the action of these muscles.
The muscles of the lips, which in carnivorous animals are
directed to the side of the mouth, are in graminivorous animals
directed to the middle of the lip over the Incisores. I have given
to these the name of D e p a s c e n t e s , from their use and destination
in enabling the animal to open its lips, so as to gather its food, and
to bite the grass. They are long muscles; one set comes down
upon the side of the face, and joining in a broad tendon, passes
over the nose to be inserted into the upper lip. Another set runs
along the lower jaw, to be inserted by a peculiar feathered tendon
into the under lip. The horse has these muscles very strong. In