g, and the sides of the head from
expanding, it allows the occipital region an entire freedom of growth;
and thus without sensibly diminishing the volume of the brain, merely
forces it into a new though unnatural direction, while it preserves, at
the same time, a remarkable symmetry of the whole structure. The
following outline of one of these skulls, will further illustrate my
meaning; merely premising that the course of the bandages is in every
instance distinctly marked by a corresponding cavity of the bony
structure, excepting on the forehead, where the action of a firm
compress has left a plane surface.

[Illustration]

This conformation, as we have already observed, was prevalent among the
old Aymara tribes which inhabited the shores and islands of the Lake of
Titicaca, and whose civilization seems evidently to antedate that of the
Inca Peruvians. I was in fact at one time led to consider this form of
head as peculiar to, and characteristic of, the former people; but Mr.
Foster's extensive observations conclusively prove that it was as common
among some tribes of the sea coast, as among those of the mountainous
region of Bolivia; that it belonged to no particular nation or tribe;
and that it was, in every instance, the result of mechanical
compression.

In my Crania Americana I have given abundant instances of a remarkable
vertical flattening of the occiput, and irregularity of its sides, among
the Inca Peruvians who were buried in the royal cemetery of Pachacamac,
near Lima. These heads present no other deviation from the natural form;
and even this irregularity I have thought might be accounted for by a
careless mode of binding the infant to the simple board, which, among
many Indian tribes of both North and South America, is a customary
substitute for a cradle. It is probable, however, that even this
configuration was intentional, and may have formed a distinctive badge
of some particular _caste_ of these singular people, among whom a
perfectly natural cranium was of extremely rare occurrence.

We are now acquainted with _four_ forms of the head among the old
Peruvians which were produced by artificial means, viz:

1. The horizontally elongated, or cylindrical form, above described.

2. The conical or sugar-loaf form, represented in the preceding
diagrams.

3. The simple flattening or depression of the forehead, causing the rest
of the head to expand, both posteriorly and laterally; a practice yet
prev