. Animal Life and the World of Nature; A magazine of Natural History. 112 Animal Life the third tooth behind the tusk in the upper jaw and likewise the third in the lower jaw are the flesh-teeth. On the other hand, the molars to the rearward of the flesh- teeth (Figs. 5 and 6) are very large, and have broad crown-surfaces surmounted with small blunt tubercles. Apparently the teeth between the tusks and the flesh-teeth are of no use to a bear, for we find them very small and falling out at an early age. As a whole, the bear's dentition is adapted to a diet of roots and fruits rather than to one
. Animal Life and the World of Nature; A magazine of Natural History. 112 Animal Life the third tooth behind the tusk in the upper jaw and likewise the third in the lower jaw are the flesh-teeth. On the other hand, the molars to the rearward of the flesh- teeth (Figs. 5 and 6) are very large, and have broad crown-surfaces surmounted with small blunt tubercles. Apparently the teeth between the tusks and the flesh-teeth are of no use to a bear, for we find them very small and falling out at an early age. As a whole, the bear's dentition is adapted to a diet of roots and fruits rather than to one of flesh; and we know that most of these animals feed chiefly on substances of the former nature, supplemented from time to time by a meal of carrion. From a certain resemblance between them it might be supposed that the molar teeth of bears and pigs are derived from a common ancestral type. Such, however, is not the case, since it has been ascertained that bears are the descendants of dog-like animals. Accordingly we may consider that their cheek-teeth have undergone a kind of retrograde or degenerate development. That is to say, the dentition, after being specialised up to a certain stage for purely carnivorous habits, subsequently underwent a further specialisation for habits of a precisely opposite nature. Although seals are as purely carnivorous as any animals, their cheek-teeth are totally different from those of the land carnivora. Fig. 7 shows in profile the dentition of the leopard-seal of the Antarctic, in which the teeth attain the extreme development of the structure charac- teristic of the true, or earless, seals in general. It will be seen that all the five pairs of cheek-teeth in each jaw are practically identical in character, and consist essentially of three sharp recurved conical cusps placed one before another; there is thus nothing to correspond with the flesh-teeth of the land carnivora. Such a type of dentition is obviously adapted to the retention of sli
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