A = Basion prealveolar point diameter
B = Its relation to length of skull
+------------------+------------------+------------------+
| Southwestern and | Northwestern | Northern Arctics |
| midwestern | | and northeastern |
+------------------+------------------+------------------+
| _A_ _B_ | _A_ _B_ | _A_ _B_ |
| 10.38 _56.4_ | 10.58 _56.4_ | 10.65 _56.2_ |
| Mean skull lengths |
| 18.41 | 18.75 | 18.96 |
+------------------+------------------+------------------+
| FEMALES |
+------------------+------------------+------------------+
| 9.85 _55.7_ | 10.06 _56.3_ | 10.06 _55.4_ |
| Mean skull lengths |
| 17.69 | 17.86 | 18.15 |
+------------------+------------------+------------------+
As in other details, so here there is a remarkable similarity between
the skulls from the three large areas, pointing both to the unity of
the people and to absence of heterogeneous admixtures. As the skull
length increases so does the basi-alveolar line, but the relative
proportions of the two remain very nearly the same.
The relative value of the basi-alveolar length in the males, compared
to the length of the skull, is in general about 0.5 per cent higher
than it is in the females. This is just about the excess of the
relative proportion of the length of the male dental arch when compared
to the same skull dimension. The general mean skull length in the
Eskimo male approximates 18.705, in female 17.899 centimeters; the mean
length of the arch is, in the male, close to 5.625, in the female 5.365
centimeters; and the percentage relation of the latter to the former
is _30.6_ in the males, _30_ in the females. The relatively slightly
greater basi-alveolar length in the males is evidently, therefore, at
least partly due to the relatively longer male dental arch, which in
turn is doubtless due to the somewhat larger teeth in the males.[156]
Notwithstanding the just discussed slight sex difference in the
Eskimo, the facial angle, i. e., the angle between the basi-alveolar
line and the line nasion-alveolar point, is equal in the two sexes.
This equalization is due largely, if not wholly, to the effect in the
males of the relatively longer basio-nasion diameter (v. a.), while
the alveolar angle, or that between the basi-alveolar and the subnasal
lines, is in general by about 1 per cent lower in the females (males,
56°; females, 55°), indicating a slightly greater slant of the subnasal
region in the female, which can only be due to a relatively slightly
shorter in this sex of the basion-subnasal point diameter. As a matter
of fact, the percentage relation of this diameter to the length of the
skull amounts in the males to _56.3_, in the females to but _55.6_.
Compared to that in the Indians, the facial angle in the Eskimo skulls
shows close affinities. Its value (69°) is very nearly the same as in
the mound skulls from Arkansas and Louisiana (males 70.7°, females
69°). In other Indians it ranges from close to 68° to 71.5°. In the
Munsee it reached 73.5°. In whites, according to Rivet's data,[157] it
ranges from about 72° to 75°; in a group of negroes it was 68.5°. In
American and other negro crania measured by me[158] it ranged from 67°
to 70.5°, in Melanesians from 66° to 68°, in Australians from 67° to
69°.
The _alveolar angle_ is more variable. It shows considerable
individual, sex, and group differences. It averages slightly to
moderately higher, which means a more open angle or less slant in the
males than in the females. In the Eskimo as a whole it was seen to
be approximately 56° in the males, 55° in the females; in the Munsee
Indians (Bull. 62, Bur. Amer. Ethn.) it was males 59°, females 57°;
in the Arkansas and Louisiana skulls (J. Ac. Sci., Phila., 1909, XIV)
it averaged males 55°, females 52°. In my catalogue material it shows
a group variation of 46.5° to 55.5° in the negro, 47.5° to 52.5° in
the Australians, 46.5° to 50.5° in the Melanesians. In the whites it
generally exceeds 60°.
Differences in facial and alveolar protrusion among the Eskimo
according to area are small, yet they are not wholly absent. The
figures below show that in the southwesterners and midwesterners, where
the skull is more rounded, the prognathism is smallest; and that toward
the north and northeast, where the skull is narrower and the palate
(dental arch) tends to become longer, prognathism increases. The "Old
Igloo" group shows once more such affinity with the Greenlanders that
it is placed with the third subdivision.