The external size of the skull is best expressed by the cranial
module or mean of the three principal diameters; the internal size,
respectively the volume of the brain, by the "cranial capacity."
The module among the southwestern and midwestern Eskimo averages 15.44
centimeters in the males and 14.77 centimeters in the females. For
people of submedium stature these are good dimensions. Fifty-two male
and 40 female skulls of the much taller Sioux (writer's unpublished
data) give the modules of only 15.25 and 14.27 centimeters; while 6
male and 9 female Munsee Indians, also tall,[144] give practically the
same values as these Eskimos, namely 15.48 centimeters for the males
and 14.75 centimeters for the females.
Not all the western groups, however, give equally favorable
proportions. In general, the coast people below Norton Sound, and
especially below the Yukon, give, so far as the males are concerned,
the lowest values. It is interesting to note that it is precisely
these people who among the western Eskimo are reputed to be about the
lowest also in culture. The Togiak and near-by Kulukak males showed,
as seen before, also about the smallest head in the living. The St.
Lawrence Island males stand just about the middle, but the females of
this island, as, interestingly, also in the living, show markedly less
favorably. The Nunivak skulls, as with the living, are somewhat above
the average, while in the small Pilot Station (Yukon) group, just as
in the near-by contingent of Marshall among the living, the males have
the largest heads in this western territory. The lower Yukon Eskimo
were also shown, it may be recalled, to be of a higher stature than
the majority of the coast people. It is a group that deserves further
attention.
The module of the female skull does not evidently stand always in
harmony with that of the male. The most striking example of this is
shown, as already mentioned, by the St. Lawrence Island females,
both skulls and the living. The females of this isolated island are
also unduly short, but their small head is not entirely due to the
defective stature. There must exist on this island, it would seem, some
conditions that are disadvantageous to the female. In the small groups,
such as that from the Little Diomede, the disharmonies are doubtless
partly due to small numbers of specimens, but there may also be other
factors, such as the bringing in of women from other places.[145]
Taking the mean of all the groups equalizes conditions, and it is seen
that the module in both sexes is almost identical with that of the more
northern groups, to Point Barrow. But the north Arctic and northeastern
groups give a cranial module that in both sexes is somewhat higher,
though their stature, according to the available data (Deniker, Boas,
Duckworth, Steensby, Thalbitzer), is not superior.
A very remarkable showing is that of the percentage relation of
the female to male skull size in the three large groupings. In the
first two it is identical, in the third it differs less than could
confidently be expected among the closest relatives. Another remarkable
fact is that this important relation is found to be much like that
in the Eskimo in various groups of Indians; thus it was _96_ in the
Indians of Arkansas and Louisiana,[4] _95.5_ in the Munsee of New
Jersey,[146] and _96.4_ in the Indian skulls of California.[147] But
it is only _93.6_ in the Sioux (52 male, 40 female skulls) and differs
more or less also in other tribes and peoples. A comprehensive study of
this relation, with due respect to age, will some day well repay the
effort.