The brain of Carnivora is, as a rule, remarkably large and well formed, in conformity with their high degree of intelligence. Its surface is thrown into well-marked ridges with intervening depressions, and presents a great contrast with the almost smooth brain of a Shrew or a Hedgehog. From it are given off nerves to the tongue, teeth, skin, muscles, and other parts of the head, as well as some to organs at a considerable distance from the head, as the heart, lungs, and stomach, and, most important of all, three pairs of nerves, one for each of the organs of the higher senses--the nose, eye, and ear. [Illustration: LONGITUDINAL SECTION THROUGH A DOG’S NOSE, SHOWING THE SPONGY BONES. (_Nat. Size. From a Sketch by T. J. Parker_) _a._ The smelling region; _b._ The sneezing region; _c._ A bristle passed through the nostril into the nasal chamber; d. A bristle passed from the nasal chamber into the passage by which the latter communicates with the mouth.] The two nerves of smell pass through a beautifully-perforated bone--hence called the “sieve-bone,” or _ethmoid_--and proceed one on each side of a bony and gristly wall which divides the two nasal chambers from one another, to a delicate membrane covering a pair of bones of wonderful complexity--a labyrinth which must be seen to be understood, for the beautiful manner in which it enfolds itself can hardly be imagined. These “spongy-bones,” as they are called, the membrane covering which forms the true organ of smell, lie in the upper and hinder part of each nasal cavity, but in front of them is a large scroll of bone, also covered by a membrane of exquisite sensitiveness, but not taking cognisance of odours. This anti-chamber, as it were, of the nose, is extremely sensitive, and its sensibility is a safeguard against intrusive dust, and deadly disease-germs. It is the _sneezing_ region, and is the natural and most careful porter of the gates of the breath. The way in which the eyes of the Carnivora are set in their head indicates their habits of life. They look straight forward, and are expressive, in the nobler kinds, of the energy and cruelty of their owner’s disposition. As in many of the Lemurs, the eye possesses what is called a _tapetum_, a sort of reflecting mirror in the bottom of the eye, which redoubles, as it were, the faint rays of evening, evidently a very important thing for these, mostly nocturnal, animals.