The Descent of Man

70. Geoffroy St.-Hilaire and F. Cuvier, 'Hist.
Nat. des Mammiferes,' 1824, tom. i.) When the
animal is excited all the naked parts become
much more vividly tinted. Several authors have
used the strongest expressions in describing
these resplendent colours, which they compare
with those of the most brilliant birds. Another
remarkable peculiarity is that when the great
canine teeth are fully developed, immense protuberances
of bone are formed on each cheek,
which are deeply furrowed longitudinally, and
the naked skin over them is brilliantly- coloured,
as just-described. (Fig. 69.) In the adult
females and in the young of both sexes these
protuberances are scarcely perceptible; and the
naked parts are much less bright coloured, the
face being almost black, tinged with blue. In the
adult female, however, the nose at certain regular
intervals of time becomes tinted with red.
In all the cases hitherto given the male is more
strongly or brighter coloured than the female,