A, with the claw retracted; B, with the claw exserted; mtc, the metacarpal; ph. 1 , the first; ph. 2, the second; ph. 3, the third phalanx; h, the bony “hood;” c, the claw; l, the elastic ligament; t, the flexor tendon; a, a ligamentous loop, through which the tendon passes.
This arrangement is of great importance, as the Cat family always attack their prey in the first instance by a stroke of the powerful fore-paw, and not, as do the Dogs, by a grip of the teeth.
Not less characteristic of the Cat family than the points we have just considered are the number and form of the teeth, which here attain the most perfectly carnivorous character, being so constructed as to be wholly incapable of grinding, thus making it impossible for their possessor to live upon any but highly nourishing animal food.
In the front part of the Cat’s upper jaw are six small teeth with chisel-like edges—three on each side of the middle line. These teeth are, in shape, not unlike our own front teeth, and, like them, are single-fanged, but their small size, when compared with those that follow, is remarkable. They are borne by a bone quite distinct in young skulls from that which carries the other teeth—the premaxillary bone—and are, therefore, classed as incisor teeth. Corresponding with them in the lower jaw are six similar teeth—the lower incisors; so that the incisors of the Cat are said to be (3–3)(3–3), that is, three on each side above and below.
LION’S CLAW, SHEATHED AND UNSHEATHED.
Following the last incisor, and separated from it by a short interval, comes on each side in both jaws a long, pointed fang, the chief means by which the Cats seize and hold on to their prey. These are the canines, or dog-teeth, and correspond to the “eye-teeth” in ourselves, those adze-like teeth immediately following and slightly projecting beyond the last incisor. When the mouth is closed the lower canines are seen to bite in front of the upper, and to fit into the space between the latter and the incisors. The canines of the Cat are written thus, (1–1)(1–1).
Following the canines, but separated from them by a slight interval or diastema, are, in the upper jaw four, in the lower three teeth, which correspond to our “grinders,” or molars and premolars. In the upper jaw the foremost tooth of this set is as small as one of the incisors, and its crown is simple, or nearly so. The next two teeth are larger and have sharp, cutting edges, divided into three points, or cusps. The second of these two teeth is much the larger, its edge is more blade-like, and the front part of its inner edge sends off a strong blunt process, which is supported by a distinct root, so that this tooth has three roots instead of two like its predecessor; it is also of much greater size than any of those in front, and, biting like a scissor-blade against the corresponding tooth of the lower jaw, is called the sectorial, or carnassial tooth. Behind it comes the last of the set, a small tooth with a transversely-set, almost flat crown.
PERMANENT TEETH OF LION.