The Descent of Man, and Selection in Relation to SexDarwin, Charles
History
The Descent of Man, and Selection in Relation to Sex
Darwin, Charles
Evolution (Biology); Human beings -- Origin; Sex differences; Sexual dimorphism (Animals); Sexual selection in animals
Professor Canestrini, after discussing the foregoing and various
analogous cases, arrives at the same conclusion as that just given. He
adduces another instance, in the case of the malar bone (40. ‘Annuario
della Soc. dei Naturalisti,’ Modena, 1867, p. 83. Prof. Canestrini
gives extracts on this subject from various authorities. Laurillard
remarks, that as he has found a complete similarity in the form,
proportions, and connection of the two malar bones in several human
subjects and in certain apes, he cannot consider this disposition of
the parts as simply accidental. Another paper on this same anomaly has
been published by Dr. Saviotti in the ‘Gazzetta delle Cliniche,’ Turin,
1871, where he says that traces of the division may be detected in
about two per cent. of adult skulls; he also remarks that it more
frequently occurs in prognathous skulls, not of the Aryan race, than in
others. See also G. Delorenzi on the same subject; ‘Tre nuovi casi
d’anomalia dell’ osso malare,’ Torino, 1872. Also, E. Morselli, ‘Sopra
una rara 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, especially, as Canestrini
has observed, in those exhumed from the Drift, and belonging to the
brachycephalic type. Here again he comes to the same conclusion as in
the analogous case of the malar bones. In this, and other instances
presently to be given, the cause of ancient races approaching the lower
animals in certain characters more frequently than do the modern races,
appears to be, that the latter stand at a somewhat greater distance in
the long line of descent from their early semi-human progenitors.
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