--------------------------------+--------------+--------------
| 10 males | 12 females
+-----+--------+-----+---------
|Cases|Per cent|Cases|Per cent
--------------------------------+-----+--------+-----+---------
Medium (about average in whites)| 2 | 20 | 2 | 17
Submedium | 5 | 50 | 2 | 17
Rudimentary | 3 | 30 | 8 | 67
--------------------------------+-----+--------+-----+---------
[Illustration: BUREAU OF AMERICAN ETHNOLOGY BULLETIN 62 PLATE 19
BRACHYCEPHALIC EXTRANEOUS FEMALE SKULL, NO. 285,311, U.S.N.M. (VIEW
FROM ABOVE), FOUND WITH THE MUNSEE INDIANS]
[Illustration: BUREAU OF AMERICAN ETHNOLOGY BULLETIN 62 PLATE 20
SKULL OF MUNSEE CHILD OF ABOUT SIX YEARS OF AGE, NO. 285,329, U.S.N.M.,
SHOWING FRONTO-OCCIPITAL COMPRESSION]
_Middle lacerated foramina. Posterior lacerated foramina._—As
repeatedly pointed out by the writer on former occasions, the middle
lacerated foramina are structures of some importance. They are very
small in the anthropoid apes, generally small in negro skulls,
submedium to medium in the yellow-brown races and in less developed
whites, and reach their maximum spaciousness in civilized modern white
men. These differences are connected with the increase in the size of
the brain. A growing brain not accompanied with a proportionate or
equally rapid increase in the bony structures of the base of the skull
(which seems to be most frequently the case) will cause a spreading and
bulging of the basal parts, one result of which will be the increased
size of the middle lacerated foramina. In the Munsee, in only two of
the nineteen skulls in which the basal region is sufficiently well
preserved for examination, the foramina about equal in size the average
in whites; in nearly half of the remaining skulls they are submedium,
and in slightly more than half they are small.
XXXV. MUNSEE CRANIA: MIDDLE LACERATED FORAMINA; POSTERIOR LACERATED
FORAMINA
--------------------+----------+----------
| 7 males |12 females
+-----+----+-----+----
|Cases|Per |Cases|Per
| |cent| |cent
--------------------+-----+----+-----+----
Medium (about as | | | |
average in whites) | 1 | 14 | 1 | 8
Submedium | 5 | 71 | 3 | 25
Small | 1 | 14 | 8 | 67
---------------------+----------+----------
| 7 males |12 females
+-----+----+-----+----
|Cases|Per |Cases|Per
| |cent| |cent
---------------------+-----+----+-----+----
Of equal size | 1 | 14 | 1 | 8
Right larger | 5 | 71 | 8 | 67
Left larger | 1 | 14 | 3 | 25
---------------------+-----+----+-----+----
The posterior lacerated or jugular foramina are of interest chiefly
because of their frequent and often marked inequality in size, which
signifies inequality in the size of the lateral sinuses and especially
of the internal jugular veins. The right foramen is frequently larger
than the left, a phenomenon which has been associated with the
prevailing right-handedness in man. In the nineteen Munsee skulls in
which the foramina could be examined, they are of about equal size in
only two instances; the right is larger in thirteen, or in two-thirds
of the cases, while the left is the larger in only four instances.
As the proportion of left-handed persons among the Indians averages
only about three per cent, it is evident that in some instances the
relation between a larger jugular canal and habitual greater use of the
arm of the same side would not maintain; besides, we know the motor
centers for the right arm and hand to be on the left side of the brain.
Possibly greater blood pressure on the right side in right-handed
persons, due directly and mechanically to the greater muscular activity
on that side, would be a more satisfactory explanation.
_Depressions of the petrous portions._—In examining the petrous parts
in the usual way, with the skull turned base upward, it is observed
that in modern men of all races, in the majority of cases, these parts
are more or less depressed below the niveau of the surrounding parts.
In reality, of course, the surrounding parts have been pressed outward
by the developing brain, while the prismatic and resistant petrous
parts remained behind. The grade of depression of the petrous parts
stands generally in close correlation with the size of the middle
lacerated foramina and is of parallel significance.[45] Among the
anthropoid apes even a slight depression of the petrous portions is
very rare, and most frequently, especially in the orang, these portions
rise slightly above the surrounding structures. In the African negro,
and occasionally in individual skulls of other inferior races, they are
level with the surrounding parts. In better developed negro skulls, as
in the majority of those of other primitive peoples, they are slightly
to moderately depressed. In white men, and in superior skulls in
general, the depression is frequently pronounced, especially, it seems,
in the brachycephals. The Indian stands in a practically intermediate
position between superior whites and the negroes, and the Munsee are no
exception. In two of the skulls the depression is well marked; in three
males and seven females it is less than the average in whites; and in
two males and five females it is only slight. The females, it will be
noted, make a poorer showing in this respect than the males.
[45] See Hrdlička, Certain Racial Characteristics of the Base of the
Skull, Science, 1901, p. 309; Proc. Assoc. Amer. Anatomists, 15th
Sess., in _Amer. Jour. of Anatomy_, I, 1901-2, pp. 508-9.