are small, scarcely longer than the incisors; and no space exists between the opposite teeth, for receiving the canines; which is an exception peculiar to man. In him, therefore, the cuspids may be regarded as a form of transition between the incisors and bicuspids, and as having no reference whatever to a flesh-eating propensity. If, however, any one be disposed to hold an opposite opinion, in consequence of the existence of the canines in man, then (to be consistent) he must believe the horse, camel, and other species of Herbivora, to be still more carnivorous than he; because the cuspids are longer in them than in man.
60. The bicuspids or false molars in man have two prominences, the outer one being generally somewhat more prominent than the inner. In the Rodentia, the Ruminants, the horse, and the elephant, there are no false molars. In carnivorous animals, they rise into high and sharp points, like saw-teeth, much larger and more prominent than those just described: they present nothing which approaches to a grinding or triturating surface; but, like those which precede them, are fitted for tearing and cutting. In this order, they are subdivided into "carnivorous" and "tuberculous" molars; the number of the latter diminishing, in proportion to the sanguinary habits of the species.
61. The molars of herbivorous animals have very large or oblong square crowns; not, however, proportionately larger than those of man, but entirely different in structure. They are composed of alternate longitudinal plates of bone and enamel; and the whole crown is surrounded with a plate of enamel, like human teeth; the grinding surface, however, is not covered by enamel, as is the case with those of man and the Quadrumana; but presents the uncovered ends of the alternate longitudinal plates of bone and enamel; and the plates of bone, being much softer than those of enamel, wear away much faster in mastication; so that the plates of enamel are caused continually to be more prominent than those of bone; whereby a roughness is given to the grinding surface, which greatly increases its dividing and triturating power upon the grass, twigs, boughs, and other vegetable and woody substances, on which herbivorous animals naturally subsist. The cheek-teeth in the lowei jaw of man, like those of herbivorous and frugivorous animals, are simply raised into rounded elevations; and are directly opposed to those of the upper jaw, so as to mash
further growth is arrested, and they afterwards wholly disappear. Roget observes, that "an organ which has served an important purpose in one animal, may be of less use in another, occupying a higher station in the scale; and the change of circumstances may even render it wholly useless. In such cases, we find that it is gradually discarded from the system; becoming continually smaller, till it disappears altogether."
