We now come to the last group of Carnivora--that of the Arctoidea--and to a family which forms an extreme limit to the long series, of which the Dogs constitute the centre, and the Cats the opposite end. The latter, as we have already seen, culminate in one direction--that is, they attain the perfection of structure for a predatory life and flesh diet. The members of the Dog family, again, are flesh-eaters, as a rule, but not exclusively. They are well adapted for hunting and catching living prey, but by no means so perfectly as the Cats; they are, indeed--from a carnivorous point of view--the inferiors of the Feline group in teeth, in claws, and in muscular strength and agility. The Bears, with which we have now to do, depart as widely from the Dogs in one direction as the Cats in the other; and their distance from the latter family is great indeed. The Cats attain the perfection of quadrupedal form, while few animals are more clumsy and awkward-looking than a Sloth Bear. Cats walk, with an elegant and silent tread, on the very tips of their toes; Bears shuffle along with a waddling, though often rapid gait, and with the whole sole of both fore and hind feet applied to the ground, or, in other words, are wholly plantigrade. Cats have a clean-cut, rounded face, with beautifully chiselled nostrils and thin lips; Bears a long snout, almost like a Pig’s. The fur of Cats is usually short and brilliantly coloured; that of Bears long, shaggy, and sombre. Lastly, while the Cats are almost exclusively flesh-eaters, many Bears are strict vegetarians, or at most eat such matters as Ants and honey, and only have recourse to meat when their favourite food cannot be had. [Illustration: TEETH OF POLAR BEAR. _i_, incisors; _c_, canines; _pm_, premolars (the second and third of which are absent in both jaws); _m_, molars.] In correspondence with the partly or entirely vegetable nature of the Bear’s diet, we find a remarkable series of modifications in its teeth. The front teeth, or incisors, are of considerable size, and have three points or cusps. The great eye-teeth, or canines, although large and formidable, are decidedly smaller in relation to the rest of the teeth than in either the Dog or Cat group. Following these are three very small teeth, which usually fall out at an early period, and are, therefore, not to be found in most skulls; these, as well as the next tooth, which is of considerable size, have their places occupied in the young Bear by “milk-molars,” and are therefore called premolars. The last premolar in the upper jaw is succeeded by two, that in the lower jaw by three, true grinders or molars; so that the “dental formula” of the Bear is the same as that of the Dog, namely, incisors, (3-3)/(3-3); canines, (1-1)/(1-1); premolars, (4-4)/(4-4); molars, (2-2)/(3-3). [Illustration: TEETH OF POLAR BEAR. The incisors and grinding teeth only are shown, the grinding surfaces of the latter being displayed.]