SUB-CLASS I. PLACENTALIA.
ORDER I. QUADRUMANA.
(Four-handed animals.)
Although in the outward appearance of the animals which constitute this Order, as well as in their anatomical structure, there is a considerable resemblance to Man, it is not nearly so great as is commonly supposed; and a minute examination shows us that even these highest forms of the brute creation are separated by a vast interval from him to whom was originally delegated the dominion over them all.
The whole conformation of Man displays that an erect position is proper to him, and that he can never maintain any other. The skull, nearly globose, rests on the spinal column, almost in an even balance; while the face, containing the chief organs of sense, occupies its frontal portion. The spine itself, enlarging to the lower extremity, is there connected with the pelvis, the form, strength, position, and broad expanse of which adapt it to support the superincumbent weight of the trunk; and this weight is now, by a beautiful mechanism, transmitted to the posterior extremities, which in the form of nearly perpendicular pillars, pursue the same general line of direction as the trunk. The articulations of the bones of the leg, both at its upper and lower extremities, are so constituted as to compel a vertical mode of progression; which is indicated also by the form and direction of the foot, by the mode in which the weight of the body is thrown upon the arch of the instep, by the projection of the heel for the attachment of the great muscles of the calf which raise the body in walking, by the breadth and flatness of the sole, and by the great toe, not having any power of opposing the others as a thumb, and therefore confining the use of the foot to that of an instrument of progression. ‘The lateral breadth of the chest, throwing the shoulders wide apart, the mode in which the head of the shoulder is jointed to the blade, the structure of the elbow, fore-arm, and hand, the position of the heart and other viscera, the influx of blood to the head, not mitigated as in the brutes by subdivision of the arteries, as well as the form, comparative development, and arrangement of the muscles of various parts of his body, prove that Man is necessitated by his whole structure to assume that erect and commanding attitude, which is so becoming to him as a moral and intellectual being.
But in these important particulars, and in many others, the detail of which would be unsuitable to the present work, the brutes differ in anatomical structure and consequent habit from Man, though in various degrees; nor does the present Order offer any exception to this diversity, though some of its highest members approach nearer than others to his form and structure in some few of these particulars.
The Quadrumana are formed for an attitude neither erect nor horizontal, but diagonal in various degrees. ‘They rest in a crouching posture, 
SKELETONS OF MAN AND ORANG.
the thighs commonly drawn up to the body, so that by a sudden extension of the knee-joint, the animals spring with great vigour and rapidity. Their progression is not by walking on the ground, though, as we shall see, some of them can effect this awkwardly, but by climbing and bounding among the branches of trees, in the dense forests where they delight to dwell. It is to fit them for these arboreal habits, that their whole structure is modified. The development of the facial portion of the skull throws the centre of gravity considerably forward of the point of its junction with the spinal column, and this requires that the spinous processes of the bones of the neck should be enlarged, for the attachment of the muscles of the back of the head. The lower vertebrae of the spine are not gradually enlarged, as in Man, and therefore possess not the power of perpendicular support which a pyramidal form supplies, while the more narrowed form and weaker structure of the pelvis, the short and powerless thigh-bones, set at an obtuse angle with the line of the trunk, the leg-bones which can be brought into the same line as the thighs only by muscular effort, while their sustaining power is weakened by their capability of rotatory motion, the weakness (arising from the mobility) of the ankle, and the lack of the pedal arch, all manifest that the natural posture of even the most man-like of the Apes is considerably removed from the perpendicular. At the same time these peculiarities of structure are most beautifully adapted to the diagonal attitude, and climbing habits which we have alluded to as proper to the animals of this Order.
But it is in the character of the extremities that the grand peculiarity of these animals resides, and by this they are separated from man by an interval wide indeed. ‘They are quadrumanous, i. e. four-handed. Each of the four extremities is furnished with four long fingers, and a short thumb projecting at an angle from the line of the fingers, and opposible to them. But poorly fitted for progression on the ground, these long grasping hands are most effective instruments for seizing the branches of trees, and thus enabling the animals to proceed by a rapid and secure course through the mazes of the forests, and to reside among their umbrageous retreats as entirely as the perching birds. Many of our readers may have often observed a Monkey use his hind-hand to take hold of any presented object; for as we have already said, the bones of the posterior limbs have the same freedom of movement that marks those of the anterior pair, and thus the extremities of the former are endowed with the versatile powers confined in man to the hands. Yet even in the Orangs and Gibbons, there is a vast inferiority in their hands to those of Man. The thumb, small, feeble, and set far back, is but imperfectly antagonistic to the fingers ; these again, greatly lengthened, and adapted thus for hooking round an object, have scarcely any power of separate motion among themselves; and the palm, instead of being hollow, is narrow, flat, and tapering from the wrist. "Compared with the hands of Man,” observes Mr. Martin,[1] “those of the Simiz are rude and imperfect instruments: constructed as tree-climbing organs, they are incapable of the manipulations which the human hand executes with the utmost facility; notwithstanding they adequately serve the wants of these animals, and harmonize with their general economy. It is therefore in accordance with their arboreal habits, that the hinder graspers of the Simiæ are as hand-like as the anterior, perhaps more so; for in these latter organs, the thumb is far more developed; never, indeed, becoming rudimentary, even in those instances in which it is the most reduced in the anterior graspers."
The principal food of these animals is fruit; of which abundance is ripe at all seasons in the tropical forests: they also occasionally prey upon the young and eggs of birds, upon lizards, and insects.
The order Quadrumana consists of three Families, Simiadæ, Cebidæ, and Lemuridæ. The first of these is scattered over the tropical regions of Africa and Asia, including the great Indian islands; the second belongs to South America; while the third is nearly confined to the great island of Madagascar, where it alone represents the Order.
- ↑ "Quadrupeds,” p. 80.