76 Mr. J. E. Harting on Forest Animals.
cud, but it will perhaps suffice if I state only what any-
one may observe who narrowly watches the actions of a
cow or a deer. The animal first grazes, by nipping off the
grass between the cutting teeth in the front of the lower
jaw and the hard pad in front of the upper jaw. Each
mouthful, instead of being masticated or chewed up, is
swallowed at once, and it continues to graze until its
hunger is appeased. It then lies down, and the process of
ruminating commences. A contraction of the flanks, a
spasmodic action in the throat, and the mouth (previously
empty) is observed to be filled with the lately swallowed
grass which has been forced up into it. The animal then
proceeds to chew this between the back teeth, or grinders,
with a slow and continuous motion of the lower jaw until
the mouthful has become reduced to pulp, when it is again
swallowed, and another mouthful is brought up to undergo
the same process ; and this goes on at intervals until most
of the food swallowed has been masticated.
The canine teeth, or what in carnivorous animals would
be called tusks, are noteworthy. In the lower jaw they
are always present, though modified so as to resemble
lateral incisors ; in the upper jaw they are generally want-
ing, although in certain exotic species (as the musk-deer,
for example) they are enormously developed, and project
outwards and downwards to a considerable length.
The grinders are six on each side of each jaw, and so
formed that their surfaces wear down unevenly by the
lateral movement to which they are subject during the
process of chewing; each tooth (as in the elephant) being
composed of alternate layers of enamel—dentine and
cementum—which, being of different degrees of hardness,
are differently affected by the grinding action.
Another characteristic feature in ruminating animals is,
that they are four-toed; they have neither thumbs nor
great toes ; and the feet are so proportioned that the axis
of the limb falls between the two middle toes, while the
inside and outside toes are much reduced in size, and
in some animals (as the camel and giraffe) are lost
entirely.