CHAPTER VI
THE SKULL AND BRAIN
Scaphocephaly popularly misinterpreted—Sutures and wormian bones Dolichocephaly—Tasmanian skulls more globose—Forehead occasionally well developed—Absence of tubera frontalia—Fronto-squamous articulation—Occipital peculiarities—Massive skull-walls—Cranial capacity—The brain—Generally well developed—Important primitive characteristics—Rhinal fissure—Insertions of neck-muscles in occiput—Atlanto-occipital articulation.
Opinion is often expressed that the Australian has not sufficient brains to completely fill his brain-box! Such a statement is, of course, not in accordance with fact. A condition known as scaphocephaly is, however, not infrequently observed in the Australian skull, which gives one the impression of insufficient inflation of the cranial vault as a whole. A sagittal ridge is present which, with a little exaggeration, might be likened to an inverted boat ([Plate V]). A similar frontal ridge is also occasionally observed in the Negroid skull and some of the fossil calvaria, but rarely in the modern European and Asiatic races.
This median frontal ridge is not the result of any abnormal thickening of bone locally, but anthropologists believe it may be connected with the early fusion of the frontal suture. As a matter of fact, the frontal suture is extremely rare in adult primitive peoples’ skulls, and so far only three have been recorded in the Australian by Dr. Ramsay Smith in specimens from the Northern Territory; one case has been found in the Tasmanian; and one or two in the Torres Strait Islanders. All the other sutures in the calvarium seem to be less complicated in the Australian than in the European and other more highly developed types of man; the most complex is the lambdoid suture; and it often has one or more small Wormian bones interposed within its course, which are, in all probability, connected with the growth of the brain, and with the consequent enlarging processes, which the enclosing bones have suffered. An os inca is occasionally seen.
Although scaphocephalic skulls are not rare among the Australians, we must not overlook the fact that occasionally we find specimens, dead or alive, exhibiting sagittal curves in no wise behind those of modern peoples. And this seems to have been even more conspicuous in the case of the lost Tasmanians.
The Australian skull is remarkably narrow and long, in most instances dolichocephalic. In the Tasmanians, the parietal portion is considerably wider in proportion; the whole of that region seems to be inflated, when compared with the frontal portion. Whereas in the Australian we noticed a sagittal ridge, a peculiar median sulcus is usually present in male skulls, running along the line of the sagittal suture.
There is a remarkable uniformity in the contours of the male Tasmanian skulls. They resemble the female Australian much more than they do the male Australian, principally because the adult male Australian skulls vary so.
We have already referred to the sloping forehead and frontal region of the Australian skull; such is observed also in the Tasmanian and, for that matter, in all primitive men whether they be recent or fossil. But at the same time, one frequently observes crania of these primitive people in which the contours of the frontals are as steep as in any average European. The last remark applies especially to the female skull, which even might occasionally show a combination of a prominent forehead with a primitive superciliary ridge. The two conspicuous eminences of the forehead of the European skull, known as the tubera frontalia, one of which is situated over either eye-socket, are not developed in the Australian or Tasmanian.
The frontal bone of the Australian skull often lies in direct contact with the squamous portion; this is, however, the case in other primitive races also. The articulation between the bones mentioned is effected by means of a process which the squamous bone sends towards the frontal; the actual line of contact measuring several millimetres. In other instances the connecting process is replaced by a small epipteric bone. The articulation may occur on one or both sides of the skull.
The bony tuberosity of the occipital bone, being part of a muscle-attachment, varies appreciably in its position; its central point is anthropologically styled the external inion. A similar protuberance on the inner surface of the bone is the divisional line between the great and small hemispheres of the brain; it is called the internal inion. The internal inion is, as a rule, situated lower than the external in the adult Australian; but in female and immature skulls the two points are at about the same level.