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become more obtuse； and that the 'cranio…facial angle' becomes more
acute by the bending down； as it were； of the facial axis upon the
cranial axis。 At the same time； the roof of the cranium becomes more
and more arched； to allow of the increasing height of the cerebral
hemispheres； which is eminently characteristic of man； as well as of
that backward extension； beyond the cerebellum； which reaches its
maximum in the South America Monkeys。 So that； at last； in the human
skull （Fig。 29）； the cerebral length is between twice and thrice as
great as the length of the basicranial axis； the olfactory plane is 20
degrees or 30 degrees on the 'under' side of that axis； the occipital
angle； instead of being less than 90 degrees； is as much as 150 degrees
or 160 degrees； the cranio…facial angle may be 90 degrees or less； and
the vertical height of the skull may have a large proportion to its
length。
It will be obvious； from an inspection of the diagrams； that the
basicranial axis is； in the ascending series of Mammalia； a relatively
fixed line； on which the bones of the sides and roof of the cranial
cavity； and of the face； may be said to revolve downwards and forwards
or backwards； according to their position。 The arc described by any
one bone or plane； however； is not by any means always in proportion to
the arc described by another。
Now comes the important question； can we discern； between the lowest and
the highest forms of the human cranium anything answering； in however
slight a degree； to this revolution of the side and roof bones of the
skull upon the basicranial axis observed upon so great a scale in the
mammalian series？ Numerous observations lead me to believe that we must
answer this question in the affirmative。
The diagrams in Figure 29 are reduced from very carefully made diagrams
of sections of four skulls； two round and orthognathous； two long and
prognathous； taken longitudinally and vertically； through the middle。
The sectional diagrams have then been superimposed； in such a manner；
that the basal axes of the skulls coincide by their anterior ends； and
in their direction。 The deviations of the rest of the contours （which
represent the interior of the skulls only） show the differences of the
skulls from one another； when these axes are regarded as relatively
fixed lines。
The dark contours are those of an Australian and of a Negro skull： the
light contours are those of a Tartar skull； in the Museum of the Royal
College of Surgeons； and of a well developed round skull from a
cemetery in Constantinople； of uncertain race； in my own possession。
It appears； at once； from these views； that the prognathous skulls； so
far as their jaws are concerned； do really differ from the
orthognathous in much the same way as； though to a far less degree
than； the skulls of the lower mammals differ from those of Man。
Furthermore； the plane of the occipital foramen （'b c'） forms a
somewhat smaller angle with the axis in these particular prognathous
skulls than in the orthognathous； and the like may be slightly true of
the perforated plate of the ethmoidthough this point is not so
clear。 But it is singular to remark that； in another respect； the
prognathous skulls are less ape…like than the orthognathous； the
cerebral cavity projecting decidedly more beyond the anterior end of the
axis in the prognathous； than in the orthognathous； skulls。
It will be observed that these diagrams reveal an immense range of
variation in the capacity and relative proportion to the cranial axis；
of the different regions of the cavity which contains the brain； in the
different skulls。 Nor is the difference in the extent to which the
cerebral overlaps the cerebellar cavity less singular。 A round skull
（Fig。 29； 'Const'。） may have a greater posterior cerebral projection
than a long one （Fig。 29； 'Negro'）。
Until human crania have been largely worked out in a manner similar to
that here suggesteduntil it shall be an opprobrium to an ethnological
collection to possess a single skull which is not bisected
longitudinallyuntil the angles and measurements here mentioned；
together with a number of others of which I cannot speak in this place；
are determined； and tabulated with reference to the basicranial axis as
unity； for large numbers of skulls of the different races of Mankind； I
do not think we shall have any very safe basis for that ethnological
craniology which aspires to give the anatomical characters of the crania
of the different Races of Mankind。
At present； I believe that the general outlines of what may be safely
said upon that subject may be summed up in a very few words。 Draw a
line on a globe from the Gold Coast in Western Africa to the steppes of
Tartary。 At the southern and western end of that line there live the
most dolichocephalic； prognathous； curly…haired； dark…skinned of
menthe true Negroes。 At the northern and eastern end of the same
line there live the most brachycephalic； orthognathous；
straight…haired； yellow…skinned of menthe Tartars and Calmucks。 The
two ends of this imaginary line are indeed； so to speak； ethnological
antipodes。 A line drawn at right angles； or nearly so； to this polar
line through Europe and Southern Asia to Hindostan； would give us a
sort of equator； around which round…headed； oval…headed； and
oblong…headed； prognathous and orthognathous； fair and dark racesbut
none possessing the excessively marked characters of Calmuck or
Negrogroup themselves。
FIG。29。Sections of orthognathous （light contour） and prognathous （dark
contour） skulls； one…third of the natural size。 'a b'； Basicranial
axis； 'b c； b1 c1'； plane of the occipital foramen； 'd d1'； hinder end
of the palatine bone； 'e e1'； front end of the upper jaw； 'T T1'；
insertion of the tentorium。
It is worthy of notice that the regions of the antipodal races are
antipodal in climate； the greatest contrast the world affords； perhaps；
being that between the damp； hot； steaming； alluvial coast plains of
the West Coast of Africa and the arid； elevated steppes and plateaux of
Central Asia； bitterly cold in winter； and as far from the sea as any
part of the world can be。
From Central Asia eastward to the Pacific Islands and subcontinents on
the one hand； and to America on the other； brachycephaly and
orthognathism gradually diminish； and are replaced by dolichocephaly
and prognathism； less； however； on the American Continent （throughout
the whole length of which a rounded type of skull prevails largely； but
not exclusively）* than in the Pacific region； where； at length； on the
Australian Continent and in the adjacent islands； the oblong skull； the
projecting jaws； and the dark skin reappear； with so much departure； in
other respects； from the Negro type； that ethnologists assign to these
people the special title of 'Negritoes。'
＇footnote＇ *See Dr。 D。 Wilson's valuable paper 〃On the
supposed prevalence of one Cranial Type throughout the
American aborigines。〃'Canadian Journal'； vol。 ii。； 1857。
The Australian skull is remarkable for its narrowness and for the
thickness of its walls； especially in the region of the supraciliary
ridge； which is frequently； though not by any means invariably； solid
throughout； the frontal sinuses remaining undeveloped。 The nasal
depression； again； is extremely sudden； so that the brows overhang and
give the countenance a particularly lowering； threatening expression。
The occipital region of the skull； also； not unfrequently becomes less
prominent； so that it not only fails to project beyond a line drawn
perpendicular to the hinder extremity of the glabello…occipital line；
but even； in some cases； begins to shelve away from it； forwards；
almost immediately。 In consequence of this circumstance； the parts of
the occipital bone which lie above and below the tuberosity make a much
more acute angle with one another than is usual； whereby the hinder
part of the base of the skull appears obliquely truncated。 Many
Australian skulls have a considerable height； quite equal to that of
the average of any other race； but there are others in which the cranial
roof becomes remarkably depressed； the skull； at the same time；
elongating so much that； probably； its capacity is not diminished。 The
majority of skulls possessing these characters； which I have seen； are
from the neighbourhood of Port Adelaide in South Australia； and have
been used by the natives as water vessels； to which end the face has
been knocked away； and a string passed through the vacuity and the
occipital foramen； so that the skull was suspended by the greater part
of its basis。
FIG。 30。An Australian skull from Western Port； in the Museum of the
Royal College of Surgeons； with the contour of the Neanderthal skull。
Both reduced to one…third the natural size。
Figure 30 represents the contour of a skull of this kind from Western
Port； with the jaw attached； and of the Neanderthal skull； both reduced
to one…third of the size of nature。 A small additional amount of
flattening and lengthening； with a corresponding increase of the
supraciliary ridge； would convert the Australian brain case into a form
identical with that of th