their perpendicular direction to the primitive convolutions. Add,' says M. Sappey, 'to the antero-posterior convolutions of the carnivora and other inferior mammals, two or three convolutions cutting them perpendicularly in the middle, and the disposition proper to the highest. mammals, particularly man and the ape, will be realised.'

Now in the brain of the orang we not only find the antero-posterior convolutions lengthened, curved, and anastomosed after the human type, but it is also in the encephalon of the same animal that those additional convolutions or 'folds of perfectionment' noticed by Professor Sappey appear the most distinctly, and offer consequently the completest analogy with the disposition of the cerebral organ in man. We are thus authorised to conclude, with Professor Mivart,1 that the difference between the brain of the orang and that of the human subject is one not of kind, but of degree. The writings of the late Professor Broca, whose careful studies in anthropology give special weight to his statements, confirm this opinion, and assert that the brain of the archencephalous animals—hominide of Owen-differs so little from that of the superior gyrencephalæ that the only distinctive characters observable in the latter are altogether secondary in importance.. 'But,' says the professor, 'these characters are not real in their nature, and even if they were, even if the cerebral hemispheres of the apes contained neither the ancyroid cavity nor the small hippocampus of man, even if we should find their cerebrum not entirely covering the cerebellum, these differences would be but slight, almost accessory, and less important than those which we meet with among animals belonging to the same order, so that

1 Man and Apes, p. 149.

they must be held altogether insufficient for the establishment of two sub-classes.'

Having thus briefly traced the points of resemblance between the human and the simian brain, and their common divergence from the type presented by other and lower races, we pass to the examination of the buccal cavity, which ought to furnish us with valuable indications respecting the mode of life of the subject under observation.

In the anthropoïd animals the mouth is disposed according to the human type. The lateral sacks, known as cheek-pouches, are absent in this species; the two excretory canals of the sub-maxillary glands (Wharton's ducts) open singly on the sides of the frænum of the tongue; the tongue itself resembles that of man; in the orang the circumvallate papillæ present the V-shaped disposition of the human type, their arrangement slightly differing in the chimpanzee and assuming the form of a T. The dental morphology and formula of the apes of the old world (catarrhines) are identical with those of man; their cuspids are, however, longer, especially in the males, and the wisdom teeth appear at an earlier age than in the human subject. The apes of the New World (platyrrhines) differ from man by the absence of one molar in each half-jaw, the place of this tooth being occupied by an extra bicuspid. The surface of the molar teeth in the human subject is characterised by the presence of an irregular ramified depression dividing it into four or five distinct tubercules. The same formation is met with in the orang, the chimpanzee, and the gorilla, as also is the superficial disposition of the enamel, which substance, in the herbivorous races, is quite otherwise distributed. Among the latter, pachydermata, ruminants (which have no incisors in the upper jaw), and rodents, the molar

teeth are composed of alternate layers of dentine, enamel, and cement, which penetrate into the interior of the tooth, so that a transverse section of it, instead of presenting an homogeneous substance surrounded by a simple enamel stratum, as in man and the quadrumana, exhibits several undulating composite folds, the dentine of which, being much less durable than the enamel, wears down rapidly, and the tooth thus acquires a rough unequal surface fitted to triturate the woody substances which form part of the alimentation of these animals. On the other hand, the carnassiers possess organs of mastication, which, according to Küss, are hardly properly called teeth, but rather spike-likeinstruments destined to tear in fragments the meat on which they feed. Their incisives, six instead of four in number in each jaw, are small, pointed, and uneven ; the surface of the molar teeth exhibits the appearance of a saw, and there usually exists but one on each side, the last bicuspid or carnassial tooth being especially characteristic. This tooth, well developed in the tiger kind, is composed of three sharp strong uneven prominences, placed one behind the other and connected by jutting ridges, the anterior prominence being doubled by an accessory spine. Nothing of this sort is observable in man or in the races which stand nearest to him. By the side of the exclusively predatory mammals we place the omnivorous types, such as the Alpine bear, the North American bear (ursus arctos), the wild boar, and the hog (sus scrofa, sus tibetanus, and sus ibericus). In the bear the surface of the molars is flattened, but the incisives number six as in the true carnivora, although they are blunter and less accentuated than the corresponding teeth of the latter. The cuspids are very long and curved, and between them and the bicuspids a remark

able interval generally exists. This character of dentition resembles the carnivorous rather than the herbivorous type, and, except that the enamel is superficially placed upon the cheek teeth, has nothing in common with the human and frugivorous morphology. The incisive teeth of the wild boar and the hog are elongated, and project forward in the direction of the axe of the maxillary bone; the cuspids, particularly those of the superior jaw, assume a special character, and develop themselves in the shape of tusks; in the lower jaw these teeth projecting outwards cross the direction of the upper pair. The same interval between the cuspids and the premolars, which we noted in the bear, exists also in the boar and pig species.

Let us now pass to an examination of the zygomatic arch and temporal region in the various orders of the mammalia. This region is important to our subject, because its disposition and aspect serve to indicate the kind of food proper to the animal. It is to be remarked that in man and in the apes the zygomatic arch is comparatively frail, slightly curved so as to present an upper concave surface, and that the temporal and masseter muscles are but little developed; while in the ruminants, although the temporal muscle does not attain any important dimensions, the masseter on the contrary manifests considerable development, and, passing beyond the zygomatic arch, attaches itself to nearly the whole of the lateral surface of the superior maxillary. Moreover, the inferior jaw of these latter animals possesses a lateral movement, which is quite characteristic, and to produce it the condyles are flattened and enabled to slide sideways in their cavity of reception. Another type of condyle is that of the rodents, which exhibits an increased diameter in the antero-posterior sense, and has a glenoid cavity similarly hollowed.

But it is pre-eminently among the carnivorous quadrupeds that we meet with the most striking variation from the human type in respect to the characters of the temporal arch. The zygomatic arch in the flesh-eating animals is extremely large, and is increased in strength by its decided curve, the direction of which is the reverse of that which we have noted in the frugivora; for the concavity is inferior in position and the upper surface is strongly convex, the curve increasing with the ferocity of the species. The dimensions, as well as the peculiar form, of this bone, and its outward projection from the skull, give strength precisely in the direction most required, and augment enormously the tearing power. Besides, the masseter and temporal muscles are strongly developed, the thickness of the latter entirely filling the large space between the zygomatic process and the temporal bone; while in height it attains the upper limit of the skull. On the other hand the internal and external pterygoidian muscles are very small, because these quadrupeds possess no lateral mobility of the jaw. This movement indeed is rendered impossible by the disposition of the glenoid cavity, the great depth of which prevents any change of position other than perpendicular opening and shutting. The omnivora differ but very slightly from the carnassiers in these respects; and it is only among the apes and above all the simians and troglodytes that we find a disposition and aspect of this articulation and muscular region perfectly analogous to those observable in man.

The classification which we have thus seen indicated in regard to the brain, the buccal cavity, the teeth and the temporo-maxillary articulation, will be confirmed by a study of the digestive canal.

The human stomach is simple, consisting, that is,