Of the Prognathous type. — The most marked feature of the typical prognathous skull, as already remarked, is the prominence of the jaws, as seen in profile (fig. 807). It is this which gives to the features of the Ne gro and Australian their peculiar ugliness ; and it is on this that the difference of the facial angle between the Negro and the Eu ropean chiefly depends. In both jaws we observe that the alveolar ridges project in such a manner, that the front teeth implanted in them meet at an angle, instead of being in the same, or in parallel planes, as in those skulls which are termed for the sake of dis tinction, orthognathic. Independently of the projection of the muzzle, however, there is an appearance of general elongation of the cranium from back to front,so that the antero posterior diameter of the cranial cavity is greater in proportion to the lateral, than it is in the oval cranium. Thus the average length of ten Negro skulls measured by Pro fessorVan der Hoeven#, was 6'96 inches, while their average breadth was 5.11 inches ; so that the relation of their length to their breadth was as P36 to P00. On the other hand, the average length of twenty European skulls was 7.04 inches, and their breadth inches ; so that the relation of their length to their breadth was P30 to P00. But this difference (which is by no means great) seems to depend rather upon the relative narrow ness, than upon the elongation, of the Negro cranium ; for it will be observed that its ab solute length is less than that of the European, and that the difference in the dimensions of the two consists chiefly in the inferior breadth. The form of the whole cranium suggests the idea of lateral compression. The tem poral muscles cover a large surface, and rise high upon the parietal bones; and the zygo matic arch has a large opening, but this is given by a forward rather than a lateral pro jection of the cheek bones. Although the forehead very commonly recedes in the prog nathous skull, this is by no means a constant character (fig. 810) ; even where it is high, however, it is seldom or never broad or full. The position of the foramen magnum has been affirmed to be, in the Negro, so far be hind the nearly central place which it holds at the base of the European skull, as to constitute a marked character of approxi mation to the quadrumanous type ; but it has been shown by Dr. Prichard, that, when due allowance is made for the projection of the alveolar processes, the position of the foramen magnum in the Negro is as central as in the other races f, its anterior border being immediately behind the trans verse line bisecting the antero-posterior dia meter of the base of the cranium. The height of the Negro skull seems to be rather less than that of the European ; but there is a more marked inferiority in the capacity of the Negro cranium, as shown by the length of the vault over the vertex, and in the circumference ; for the former averaged, in the measurements of Professor Van der lioeven, inches in the Negro, and 14.67 inches in the European ; whilst the average of the latter was 19.75 inches in the Negro, and in the European. Although Pro fessor Tiedemann attempted to prove*, by filling the cranial cavity with millet-seed, and then weighing the quantity which it was found to contain, that the capacity of the Negro's cranium is equal to that of the Eu ropean's, yet, as Professor Van der Hoeven has pointed out, the average capacity of the Negro skulls thus examined by Tiedemann was about one-twentieth less than the average capacity of European skulls. On the other hand, the facial portion of the prognathous skull is relatively, and even absolutely larger. It has been usually described as being cha racterised by the large relative size of the parts subservient to the organs of the senses ; hut although it certainly appears that both the anterior and posterior nares are wider than in the European, that the nasal cavity is altogether more capacious (so as to allow a more extended surface for the distribution of the olfactive nerve), and that the external auditory meatus is remarkably large, it does not appear that the same holds good of the orbits, which, though sometimes larger, are sometimes smaller than in the average of Europeans. t This prognathous type, although most re markably developed among the Negroes of the Delta of the Niger, is by no means confined to them, nor to the African races in general, of which it is usually regarded as characterigtic. Tt is met with among in habitants of various quarters of the globe ; but is nearly always associated with squalor and destitution, ignorance and brutality. In stead of following an agricultural or pas toral life, the people among whom it pre vails are, for the most part, hunters, or inhabitants of low marshy forests, dependent for their supplies of food upon the chase, or upon the accidental produce of the soil, and but little advanced in any of the arts which are characteristic of civilisation. Such is the character of those aborigines of Australia, and of certain islands of the Polynesian Ar chipelago, amongst whom the prognathous type is presented almost, if not quite, as characteristically as among the Negroes of the Guinea coast.
The skulls of some of these inferior races have been asserted by Dr. John Neill* to pre sent a division of the articulating surface of each occipital condyle into two facets, by a groove or ridge ; which appears to The the persistent indication of the fissure that originally separates the basi-occipital bone from the ex-occipitals. This character, how
ever, is far from being constant in any one family. Thus it was only found in 30 out of 81 African crania ; whilst it presented itself in only 4 pure Egyptian heads in Dr. Mor ton's collection, in 3 out of 105 skulls of aboriginal Americans, and in none of the other 129 skulls of different nations whose history was well known. Thus, although more common among the African races than in the others, and marking in them (like the occasional persistence of the separate inter maxillary bone to a later period than usual) a less complete development, yet its presence in but little more than one-third even of the Negro-crania, and its occasional existence elsewhere, altogether destroy its title to be considered a mark of separation between dif ferent branches of the human family. The writer has looked for this character in at least twenty African crania, without once meeting with it ; the only skull which unequivocally presented it being that of a Tasmanian female, 14.—Dr. Neill points out, also, that the lower boundary of the anterior nares in the Negro skull wants the sharp edge which is found in the higher races ; and that this, also, may be regarded as a retention of the foetal type. This character, however, is at least as strongly marked in Australians as in Negroes ; and an approximation to it is shown wherever there is a tendency to the prognathous conformation.
Of the pyramidal type. — The most striking feature in this type of cranial conformation, which is best seen in the front and basal views (figs. 811. 813.), is the lateral or out ward projection of the zygomatic arches ; this is principally due to the peculiar form of the malar bones, whose facial surface is very broad and flat ; but partly, also, to that of the zygomatic process of the temporal bone, which forms a large rounded sweep. From this peculiarity, in conjunction with the nar rowness of the forehead, it results that lines drawn from the zygomatic arches, touching the temples on either side, instead of being parallel, or nearly so, as amongst Europeans, meet at no great distance over the forehead, so as to form, with the line joining their bases, a triangular figure. The upper part of the face being retnarkably flat, the nose also being flat, and the nasal bones, as well as the space between the eyebrows, being nearly in the same plane with the cheek-bones, the trian gular space bounded by these lines may be compared to one of the faces of a pyramid. This, however, is by no means the most im portant peculiarity of this type ; for the shortness of the antero-posterior diameter of the cranium, in relation to the lateral, is, as pointed out by Professor Retzius, at least equally characteristic. Thus the average length of sixteen Laplander's skulls measured by him was about 6.90 inches, while the average breadth was as much as 518 inches ; making the proportion of the former to the latter no more than 1.20 to 1.00. The greatest longitudinal dimension among all these skulls was only 7.08 inches, while the greatest late ral extension was as much as 6.16 inches ; thus reducing the proportion to 1.13 to POO.
The orbits in these skulls are large and deep ; and the peculiar conformation of the bones which surround them give to the aperture of the lids an appearance of obliquity, the inner angle being directed downwards (fig. 814).
The whole face, instead of approaching the oval, as in Europeans, is of a lozenge-shape; and the greater relative development of the zygomatic bones, and of the bones of the face altogether, when compared with the capacity of the cranium, indicate in the pyramidal skull, as in the prognathous, a more ample develop ment of the organs immediately subservient to sensation ; the lateral expansion being attended with a similar result in this respect, to that which is consequent upon the forward prolongation of the prognathous skulls. In the breadth of the lower jaw (fig. 813) a remarkable contrast will be noticed with that of the prognathous type (fig. 809). The greater part of the races representing the pyramidal type in a well marked degree, may be designated as pastoral nomades ; some of them wandering with their flocks and herds over the vast plains of high Asia, whilst others creep along the shores of the Icy sea, supporting themselves partly by fishing, but living in part upon the flesh of their rein-deer. As in the preceding case, however, the same type is encountered in a remote quarter of the globe, among tribes whose descent would seem to be altogether different, yet which closely corresponds with the nomadic races of high Asia as to the physical conditions under which they live ; namely, the Hottentots of South Africa, whose resemblance to Mon golians in cranial conformation, as well as in complexion, hair, and several other charac ters, is so striking as to have been noticed by all travellers familiar with both, and to have given rise to many speculations as to their possible blood-relationship. It will be here after shown, however, that there is no valid reason for separating the Hottentots from the general mass of the African nations ; and just as the Australians repeat the progna thous type at a distance from its chief centre, with a slight admixture of the pyramidal, so do the Hottentots in some degree repeat the pyramidal, with an admixture of the prog nathous.