28 CRANIA BRITANNICA. [CHAP. III.
facility for the brain they contain to expand by growth. And at a late time of life, variable in
diifcront persons, the sutures themselves become more or less effaced, so that the brain-case is
by this means at times converted into a continuous hollow spheroid.
Ih^ frontal hone is the bone of the forehead, and in shape a good deal resembles a scallop
shcU. At its lower part, in the centre, is a rough stu-face upon which the upper ends of the
small nasal bones rest; and at the sides it has two thin horizontal plates, which extend backwards
over the eyes, and constitute a large portion of each orbital cavity, or its roof. Immediately
above the central portion supporting the nasal bones a prominence occurs in many
skulls. It marks the situation of two cavities, called frontal sinuses, formed in the substance
of the bone by the separation of the two tables or layers of which this, lUie the other bones of
the calvarium, consists. Extending oiitwards from each side of tliis prominence, are the superciliarij
ridges, in the situation of the eyebrows. The sizo of the frontal sinuses varies in the
different races. In the Australians, although the prominence is remarkably developed externally,
the internal cavity is either wanting or very small. In an ancient Briton's skull from the Green
Grate Hill Barrow near Pickering, the frontal sinuses are two triangular cavities of large size,
separated ia the centre by a thin plate of bone; each extending, in one dii'ection, outwards,
along the superciliary ridge, for an inch and a half, and, in another, backwards, for an inch and
fom'-tenths, over the top of the orbital cavity on its inner side; and each large enough to hold
the tip of the thumb. Immediately above and somewhat between the prominences caused by the
frontal sinuses, in the centre of the outer sm-face of the bone, is a smooth sm-face called the
glabella. Above the glabella, and a little on each side, an elevation of the bone is generally
seen, called the/)'o»teZ eminence. The frontal bone covers the anterior lohes of the brain, which
are supported upon its orbital plates. In some adult skulls it is divided iato two by a suture
running down the middle of the forehead, called ihe frontal suture, which, however, is most
commonly effaced at an early period of life. It is connected with the parietal bones by the
coronal suture. The frontal bone varies greatly in size and form in different individuals, and
the different races of men*. And it is upon its salient or recedent outline that the greater or
less extent of the facial angle mainly depends. The parietal hones are two irregularly foursided
bones, which form the sides and top of the roof of the skull. Near the middle of each is a
prominence called the parietal eminence. They are connected together along the centre of the
vertex, or top of the head, by the sagittal suture, on each side below by the squamous suture to
the temporal bones, and behind by the lambdoidal suture to the occipital bone. They give
protection to the middle lohes of the hemispheres of the brain. The parietal bones in some
races, especially the Esquimaux and some of the American tribes, are joined together at a less
than usually obtuse angle, so as to form a prominent ridge running all along the top of the
skull,—which constitutes, together with unusual wideness of the cheek-bones and zygomatic
arches, the prjramidal skull of Dr. Prichard. The occipital hone is situated behind the parietal
bones, forming aU. the back part, and by its basilar process {basioccipital of Owen), the central
portion of the base of the calvarium. This bone gives protection to the posterior lohes of the
brain, and nearly the whole of the cerebellum, or little brain; is pierced at the IcJwer part by the
; magnum, or great hole, through which the spinal marrow is continued upwards to the
* Dr. Vimont uses an ingeniods comparative method to exhibit
these differences with great accuracy. He projects a
uniform square of lines as large as the largest frontal hone, divided
by cross lines into nine equal panels numbered, over each
frontal bone set upon its orbital edge.—Traité (le Phriînologie,
planche 109, 2' éd. 1838.
CHAP. III. ] ANATOMICAL EXPLANATIONS. 29
brain; and is articulated below by the two condyles, mth the first bone of the vertebral column
or spine, the vertebra called the Atlas*. It is marked by a projection at its upper part, called
the occipital eminence, and a rough prominence at the back of the skuU named the occipital
protuberance, from which an elevated Une descends downwards, the occipital spine ; and is joined
to the parietal and temporal bones by the lambdoidal suture. The advanced position of the foramen
magnmn in the base of the calvarium, which brings the spine more under the centre of the
head to conform to the erect position of man, is one strongly marked characteristic of the human
skull, as distinguished from that of the lower animals, the antlu-opoid apes even. The projection
of the occipital eminence differs much in the two sexes, and in different races. In the skulls
of women it is much more j)romiaent than in those of men, and in those of the Esquimaux it is
also pronounced. Dr. Bellamy first pointed out the existence of B.I:L interparietal bone {superoccipital
of Owen) in the crania of mummies of the ancient Peruvians of tender age. Dr. Tschudi
considers it an osteological anomaly proper to the Peruvian race. The peculiarity consists in
the thin or scaly ascending portion of the occipital bone being separated from the rest by a
transverse suture running above the occipital protuberance—so as to produce a distinct
triangular bone. This arrangement is seen in the first months after birth, yet Dr. Tschudi
acquaints us that in all the skulls he examined he was able to perceive traces of such structure,
even where the interparietal had become completely umted to the occipital. This isolation of
the scaly portion of the occipital, constituting the snperoccipital of Owen, is a permanent form
in some of the mammalia, intra-uterine in man, and rarely, as in a skull from a Roman burialplace
at Eelisstow, Suffolk, preserved in the Anatomical Museum at Cambridge, and in the
cranium of a Bengalee, for which we are indebted to the kindness of Dr. Spry of Bath,
continuing to matm'e age. The peculiarity is seen in one of the Peruvian skulls figured by
Morton (Chimuyan, pi. 5), and most distinctly in that of Wan-yunta, a Chief of the Cayugas,
a New York tribe, who was nearly a hundred years old at his death (pi. 35). Morton's
outlines render it jn-obable that traces of this peculiarity are not very uncommon in American
skulls. TFormian or triquetral bones are occasional, irregular, and anomalous small bones, at
times met with in the course of the lambdoidal suture, and appear to be detached rudimentary
elements of this snperoccipital bone. The temporal bones are situated one on each side of the
skuU, immediately below each parietal bone. Anatomists distinguish in each temporal bone a
thin squamous or scaly portion, wMch passes upwards to join the parietal and complete the side
waU of the calvariimi {squamosal of Owen), and petrous or wi^j portion (petrosal of Owen),
forming a massive bone in which is developed those osseous cavities and canals proper to the
internal ear, and which projects inwards, so as to contribute to the base of the calvarium. The
squamous portion gives origin to the zygomatic process, wliich passes horizontally forwards to
join a similar process of the malar bone, and thus to form the arch of the zygoma, or yoke.
The petrous portion bears the maMoid process {mastoid of Owen), and contains the external
auditory canal which communicates Avith the intricate chambers of the ear. It is a bone oi
* The occipital sometimes presents a prominence or process
outside the condyle {paroccipital of Owen), which is constant
in many mammalia. In Eurojieans it is rare and anomalous,
and usually seen on one side only. In the skull of an Esquimaux
from Lancaster Sound, which we owe to the adventurous
navigator Captain E. A. Inglefield, this process is present of
great size, but on the left side only—it is something more than
half an inch long, and nearly as much in diameter. In a Saxon
skull from Leipzig it also occurs on the left side only, is somewhat
longer, but of little more than half the diameter; and
in an ancient Iloman skull of a woman derived from a Roman
cemetery near Lincoln, for.which we are indebted to the great
pains and obliging politeness of the Rev. Ed. Trollope, F.S.A.,
it is again seen on the same side, and equally long and slender.