The Descent of Man

ara anomalia dell' osso malare,' Modena, 1872.
Still more recently Gruber has written a pamphlet
on the division of this bone. I give these
references because a reviewer, without any
grounds or scruples, has thrown doubts on my
statements.), which, in some of the Quadrumana
and other mammals, normally consists of
two portions. This is its condition in the human
foetus when two months old; and through arrested
development, it sometimes remains thus
in man when adult, more especially in the
lower prognathous races. Hence Canestrini
concludes that some ancient progenitor of man
must have had this bone normally divided into
two portions, which afterwards became fused
together. In man the frontal bone consists of a
single piece, but in the embryo, and in children,
and in almost all the lower mammals, it consists
of two pieces separated by a distinct suture.
This suture occasionally persists more or
less distinctly in man after maturity; and more
frequently in ancient than in recent crania, es-