But though the number agrees, the form is very different. The incisors and canines, as we have said, exhibit no difference of importance, but the last premolar and all the molars, instead of having the sharp cutting character they have in the Cat, and to a less degree in the Dog, have comparatively flat crowns, raised up into a number of little elevations or tubercles; even the “carnassial” teeth (last premolar in the upper jaw, and first molar in the lower) have entirely lost their scissor-blade character, and become true grinders. As a corresponding change, the hinge of the lower jaw is no longer so constructed as to be incapable of any but an up and down motion; it can, on the contrary, be worked from side to side, so that the Bear can actually _chew_ his food. The animal derives a double advantage from this: in the first place, the food can be reduced to a pulp, a very necessary thing for such food-materials as roots, which in an entire state would be highly indigestible; and, in the second place, it is acted upon for a considerable time by the saliva, and thus partially digested in the mouth, for one of the chief properties of saliva is to convert the insoluble, and therefore indigestible, starchy matter, of which a large part of most vegetable substances consists, into soluble, and therefore digestible, sugar. It is a remarkable circumstance that the teeth have the same form in all the Bears: though, as we shall see, while most of them are wholly or largely herbivorous, some, such as the Polar Bear, are almost entirely of flesh-eating habits, and one would naturally expect a difference in the teeth. Curiously enough, however, no such difference is apparent. The Bears have five toes to each foot, all armed with long curved claws. In the skull the floor of the drum cavity of the ear is hardly at all dilated, so that there can scarcely be said to be a _bulla tympani_ at all; moreover, a bony passage of considerable length leads from the drum to the exterior, instead of the aperture being flush with the wall of the drum, as in the Cats. As we have seen, the Cats have a small _cæcum_, or blind process, to the intestine, and the Dogs one of considerable size. In the Bear this appendage is wholly absent. [Illustration: FEET OF BEAR.] Bears are found over a large part of the world, in Europe, Asia, North and South America, and North Africa. They are, however, wholly absent from what is termed trans-Saharal Africa, that is, the part of the continent south of the great Sahara Desert; and are also not to be found in any part of the Australian region, or, in other words, in Australia, Tasmania, New Zealand, and the islands of the Malayan Archipelago east of Wallace’s line. They thus have a far more restricted distribution than either of the other two chief families of Carnivora--the _Felidæ_ and _Canidæ_. THE COMMON BROWN BEAR.[139]