The Book of Household Management by Mrs. Beeton

noticed. The bodies of nearly the whole species are covered with hair, a kind of clothing which is both soft and warm, little liable to injury, and bestowed in proportion to the necessities of the animal and the nature of the climate it inhabits. In all the higher orders of animals, the head is the principal seat of the organs of sense. It is there that the eyes, the ears, the nose, and the mouth are placed. Through the last they receive their nourishment. In it are the _teeth_, which, in most of the mammalia, are used not only for the mastication of food, but as weapons of offence. They are inserted into two movable bones called jaws, and the front teeth are so placed that their sharp edges may easily be brought in contact with their food, in order that its fibres may readily be separated. Next to these, on each side, are situated the canine teeth, or tusks, which are longer than the other teeth, and, being pointed, are used to tear the food. In the back jaws are placed another form of teeth, called grinders. These are for masticating the food; and in those animals that live on vegetables, they are flattened at the top; but, in carnivora, their upper surfaces are furnished with sharp-pointed protuberances. From the numbers, form, and disposition of the teeth, the various genera of quadrupeds have been arranged. The _nose_ is a cartilaginous body, pierced with two holes, which are called nostrils. Through these the animal is affected by the sense of smell; and in some it is prominent, whilst in others it is flat, compressed, turned upwards, or bent downwards. In beasts of prey, it is frequently longer than the lips; and in some other animals it is elongated into a movable trunk or proboscis, whilst, in the rhinoceros tribe, it is armed with a horn. The _eyes_ of quadrupeds are generally defended by movable lids, on the outer margins of which are fringes of hair, called eyelashes. The opening of the pupil is in general circular; but to some species, as in those of the Cat and Hare, it is contracted into a perpendicular line, whilst in the Horse, the Ox, and a few others, it forms a transverse bar. The _ears_ are openings, generally accompanied with a cartilage which defends and covers them, called the external ears. In water-animals the latter are wanting; sound, in them, being transmitted merely through orifices in the head, which have the name of auditory-holes. The most defenceless animals are extremely delicate in the sense of hearing, as are likewise most beasts of prey. Most of the mammiferous animals _walk_ on four feet, which, at the extremities, are usually divided into toes or fingers. In some, however, the feet end in a single corneous substance called a hoof. The toes of a few end in broad, flat nails, and of most others, in pointed claws. Some, again, have the toes connected by a membrane, which is adapted to those that are destined to pass a considerable portion of their lives in water. Others, again, as in the Bat, have the digitations of the anterior feet greatly elongated, the intervening space being filled by a membrane, which extends round the hinder legs and tail, and by means of which they are enabled to rise into the air. In Man, the hand alone comprises fingers, separate, free, and flexible; but Apes, and some other kinds of animals, have fingers both to the hands and feet. These, therefore, are the only animals that can hold movable objects in a single hand. Others, such as Rats and Squirrels, have the fingers sufficiently small and flexible to enable them to pick up objects; but they are compelled to hold them in both hands. Others, again, have the toes shorter, and must rest on the fore-feet, as is the case with dogs and cats when they wish to hold a substance firmly on the ground with their paws. There are still others that have their toes united and drawn under the skin, or enveloped in corneous hoofs, and are thereby enabled to exercise no prehensile power whatever.