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the ruminants, the horse, and the elephant. But in the carnivora they rise into high and sharp points, like the teeth of a saw, much larger and more prominent than in man, and with nothing that can adapt them to grinding food; but, like the canine teeth, they are fitted for tearing and cutting.
4. The Grinders of herbivorous animals are strongly contrasted to the cheek teeth of the carnivorous. With the former they are made for mashing and grinding, having square crowns, kept rough by their formation of bone and enamel alternately, since the bone wears away faster than the enamel. But the cheek teeth of the carnivora, above and below, shut into one another, and act as the teeth of a saw or a pair of shears, so as to cut and hold fast. To these our molar teeth are quite unlike, but greatly resemble the cheek teeth of both herbivorous and frugivorous animals.
Articulation of the Lower Jaw.—The jaws of carnivorous animals, when closed, are tightly locked together by the teeth fitting into one another above and below, and also by the shape of the bones, which admit of no movement of the jaw but upward and downward. On the contrary, for grinding vegetable food the herbivorous jaw has a considerable power of sideway motion, for which the joint and socket are adapted. In man also, the lower jaw has much freedom of lateral movement, which aids in grinding the food between the molars. The quadrumana (or four-handed—i.e., apes and monkeys) have a similar articulation of the jaw. Thus, again, we find the human anatomy to resemble that of the herbivora and frugivora, but to be contrasted to that of the carnivora.
Zygomatic Arch—Temporal and Másétér Muscles.—Flesh-eating animals, needing to seize, hold, and even carry their prey in the mouth, must have huge muscles to their jaws, and large cheekbones as a base of the muscles. The power of the cheek muscle (called the másétér, or "chewer") is generally proportioned to the span and spring of the arch of the cheekbone. In the carnivora this arch is of great size and strength, extending both backward and upward, and the champing muscle is so large as to swell out the cheek immensely. In ruminants the arch is short, and the muscles of the temple small. They have the muscles for the side-movement of the jaw largely developed, which are extremely small in the carnivora. In man also the arch is small, the muscles of the temple moderate, and the force of the jaws comparatively weak.
Salivary Glands.—These glands do not exist in fishes, and are feebly developed in amphibious mammalia. They are small in the carnivora, whose food needs little chewing and little saliva added to it. Saliva (water in the mouth), and the glands which produce it, are most needed where there is most mastication, as especially where the cud is to be chewed. In all the herbivora
