The Races of Man: An Outline of Anthropology and Ethnography

by Joseph Deniker

All the other characters which distinguish man from the anthropoid apes are only the consequences of the great enlargement of his brain-case, at the expense of the maxillary part of the face, and of the erect attitude and biped progression.

Let us take, for instance, those enormous crests which give an aspect at once so strange and horrible to the skulls of the adult males of the gorilla and the chimpanzee. These projections are due to the extreme development of the masticatory muscles which move the heavy jaws and of the cervical muscles, ensuring the equilibrium of the head. Not having found sufficient room for their insertion on the too small brain-case, they have, so to speak, compelled the bony tissue in the course of development to deposit itself as an eminence or crest at the point where the two lines of insertion meet on the crown of the head. The best proof of this is that the young have no crests, and that on their skulls the distance between the temporal lines marking the insertion of the temporal muscles is almost as great as it is in man. In the gorillas, it is the same with the enormous spines of the cervical vertebræ, to which are fixed the muscular masses of the nape of the neck. These crests and these processes being less developed in the orang-utan, its head is not so well balanced, and its heavy muzzle falls on its chest. So one may suppose that the laryngeal sacs, considerably larger than those of the gorilla, serve him as air-cushions to lessen the enormous weight of the jaw resting on the trachea. The gibbon, better adapted to biped progression, and having a less heavy jaw, has no skull-crests. Further, with it, the ventricles of Morgagni, that is to say, the little pouches situated behind the vocal cord in the larynx, never develop (except in one species, Hylobates syndactylus) into enormous air-sacs as in the orang-utan. In this respect, the gibbon approaches much nearer to man than the other anthropoids, but it is also more distinguished from him than the others by the excessive length of the arms, or, to be more exact, of the pectoral limbs. It holds itself erect and walks almost as well as man, aided by the long arms and hands which touch the ground even when the animal is standing quite upright, and which he uses as a pendulum when walking. In the case of three other anthropoids, which bend forward in walking, the pectoral limb is shorter than in the gibbon but longer than in man.

The first toe, opposable in the anthropoid apes and unopposable in man, the relative length of the toes and fingers generally, etc., only constitute modifications correlative to the erect attitude and biped movement of man, and to his terrestrial habitat as opposed to the arboreal habitat of the anthropoid apes, and to their biped movement necessitating the support of the hands.

The differences in the form and size of the teeth are also the consequence of the inequality of the development of the maxillary part of the face in man, and in the apes in general.

The size of the teeth in proportion to that of the body is less in man than in the apes (Figs. [1] and [2]). Putting aside the incisors and the canines, the size of the molars and the premolars of these animals is larger in relation to the length of the facial portion of the skull. The “dental index” of Flower, that is to say the centesimal relation of the total length of the row of molars and premolars to the length of the naso-basilar line (from the nasal spine to the most advanced point of the occipital foramen), is always greater in the anthropoid apes than in man; in the latter it is never above 47.5, while it is 48 in the chimpanzee, 58 in the orang, and 63 in the gorilla.

As to the arrangement of the teeth on the alveolar arch, with man they are in a compact line forming a continuous series without any notable projection of any one tooth above the common level; while in all the apes is observed an interval (diastema) between the canines and the lateral incisors of the upper jaw, and between the canines and the first premolars of the lower jaw. These gaps receive in each jaw the projecting part of the opposite canine.

Like the anthropoid apes, man has five tubercles in the lower molars, while the monkeys have in general only four. This rule admits, however, of numerous exceptions: very often the fifth posterior tubercle is wanting in the two last molars in man; on the other hand, it is regularly found in the last molar in certain kinds of monkeys (Cynocephali, Semnopitheci). As to the wisdom tooth, in certain pithecoid apes (Cynocephali, Semnopitheci) it is greater in size than the anterior molars; whilst in certain others, like the Cercopitheci, it is much less than the two first molars. With the anthropoid apes this tooth is of the same size as the other molars or a little smaller, and it is generally the same with man, though in somewhat frequent cases it is entirely wanting. The dental arch is different as regards form in man and in apes. In man it has a tendency towards the parabolic and elliptical form, whilst in apes it usually takes the form of U.

It should be noted that all the characters that distinguish man from the anthropoid apes have a tendency to become more marked with the development of civilisation and life in a less natural environment, or artificially modified, as we have already seen in regard to the curves of the vertebral column. Thus the absence of the fifth tubercle in the lower molars has been more often noted in European races (29 times out of 51, according to Hamy) than with Negroes and Melanesians. The wisdom tooth seems to be in a state of retrogressive evolution among several populations. Especially in the white races it is nearly always smaller than the other molars; the number of the tubercles is reduced to three instead of four or five; very often in the lower jaw it remains in its alveola and never comes through.

In the same way the little toe tends, in the higher races (perhaps owing to tight boots), to become atrophied and formed of but two phalanges instead of three. Pfitzner has noted this reduction in thirty feet out of a hundred and eleven that he examined.[20]

It is perhaps in similar retrogressive evolutions due to the “social environment” that we must seek the explanation of a great number of characters of “inferiority” and “superiority,” so called, of certain races.