The mode of feeding and the form and number of the teeth of necessity correspond: tearing and gnawing are processes that need teeth like knives and scissors, while grinding or chewing require teeth like millstones. Both these kinds exist in the Bear. In the Dog the crushing teeth become less in size and importance; in the Lion they are suppressed, and all the teeth have a cutting character, their number being at the same time much reduced. The teeth are often all that remains of certain extinct creatures; they are, therefore, a most important part of the anatomy of an animal, as well as being of great service in the matter of classification or grouping. They are the hardest of all the organs; their relation to the food of the species, and their necessary correlation to the digestive organs, makes them serve as a key to the rest of the creature’s structure, which structure is in absolute harmony with its habits and daily life. [Illustration: STOMACH OF LION.] The tongue is covered with horny projections, or papillæ, and in the Cat tribe serves as a rasp to rub and scrape off the smaller fragments of flesh from the bones. The stomach is always simple, that is, consists of a bagpipe-like cavity not divided into compartments, as in the Ruminants and some other animals. A great difference from herbivorous animals is also seen in the length of the intestine. As the food is of a highly nourishing nature it requires less time for its digestion, and a smaller surface for its absorption into the blood, and the intestine is therefore remarkably short--not more than three times the length of the body in the Lion and Wild Cat, instead of being fifteen to thirty times the length, as in some vegetable feeders. The Carnivora have, therefore, the manifest advantage of a more compact and smaller “barrel” than the Herbivora, and, in consequence, have less weight to carry, and are slim and slender-waisted. As might naturally be expected, the organs by which the blood, loaded with nourishment from the digestive canal, is carried to all parts of the body, are well developed. The heart, if not “as hard as the nether millstone,” is yet compact and strong in the highest degree: the circulation is vigorous, and the result is seen in great courage and astonishing powers of endurance. [Illustration: BRAIN OF DOG.] In the lungs, with the windpipe and larynx, in which the multitudinous cries of the group--barks, howls, roars, and whines--are produced, there is nothing to merit any special mention.