be supposed that they have been developed merely for the sake of
exciting fear in their enemies. One of the above-named antelopes, the
Portax picta, has a large well-defined brush of black hair on the
throat, and this is much larger in the male than in the female. In the
Ammotragus tragelaphus of North Africa, a member of the sheep-family,
the fore-legs are almost concealed by an extraordinary growth of hair,
which depends from the neck and upper halves of the legs; but Mr.
Bartlett does not believe that this mantle is of the least use to the
male, in whom it is much more developed than in the female.
[Fig. 68. Pithecia satanas, male (from Brehm).]
Male quadrupeds of many kinds differ from the females in having more
hair, or hair of a different character, on certain parts of their
faces. Thus the bull alone has curled hair on the forehead. (15.
Hunter s Essays and Observations, edited by Owen, 1861. vol. i. p.
236.) In three closely-allied sub-genera of the goat family, only the
males possess beards, sometimes of large size; in two other sub-genera
both sexes have a beard, but it disappears in some of the domestic
breeds of the common goat; and neither sex of the Hemitragus has a
beard. In the ibex the beard is not developed during the summer, and is
so small at other times that it may be called rudimentary. (16. See Dr.
Gray s Catalogue of Mammalia in the British Museum, part iii. 1852,
p. 144.) With some monkeys the beard is confined to the male, as in the
orang; or is much larger in the male than in the female, as in the
Mycetes caraya and Pithecia satanas (Fig. 68). So it is with the
whiskers of some species of Macacus (17. Rengger, Saugethiere, etc.,
s. 14; Desmarest, Mammalogie, p. 86.), and, as we have seen, with the
manes of some species of baboons. But with most kinds of monkeys the
various tufts of hair about the face and head are alike in both sexes.
The males of various members of the ox family (Bovidae), and of certain
antelopes, are furnished with a dewlap, or great fold of skin on the
neck, which is much less developed in the female.
Now, what must we conclude with respect to such sexual differences as
these? No one will pretend that the beards of certain male goats, or
the dewlaps of the bull, or the crests of hair along the backs of
certain male antelopes, are of any use to them in their ordinary
habits. It is possible that the immense beard of the male Pithecia, and
558