This last must be the surface, the contour of which is shown in Fig. 24,
A., below 'b'. It is particularly interesting, as it suggests that,
notwithstanding the flattened condition of the occiput, the posterior
cerebral lobes must have projected considerably beyond the cerebellum,
and as it constitutes one among several points of similarity between the
Neanderthal cranium and certain Australian skulls.

Such are the two best known forms of human cranium, which have been
found in what may be fairly termed a fossil state. Can either be shown
to fill up or diminish, to any appreciable extent, the structural
interval which exists between Man and the man-like apes? Or, on the
other hand, does neither depart more widely from the average structure
of the human cranium, than normally formed skulls of men are known to
do at the present day?

It is impossible to form any opinion on these questions, without some
preliminary acquaintance with the range of variation exhibited by human
structure in general--a subject which has been but imperfectly studied,
while even of what is known, my limits will necessarily allow me to
give only a very imperfect sketch.

The student of anatomy is perfectly well aware that there is not a
single organ of the human body the structure of which does not vary, to
a greater or less extent, in different individuals. The skeleton varies
in the proportions, and even to a certain extent in the connexions, of
its constituent bones. The muscles which move the bones vary largely
in their attachments. The varieties in the mode of distribution of the
arteries are carefully classified, on account of the practical
importance of a knowledge of their shiftings to the surgeon. The
characters of the brain vary immensely, nothing being less constant