h
a curiously distinctive white stripe above the tail, which is nearly
concealed when the animal is at rest by a fold of skin but comes into
full view when it is in motion, being thus quite analogous to the
upturned white tail of the rabbit. In the pallah the white rump-mark is
bordered with black, and the peculiar shape of the horns distinguishes
it when seen from the front. The sable-antelope, the gems-bok, the oryx,
the hart-beest, the bonte-bok, and the addax have each peculiar white
markings; and they are besides characterised by horns so remarkably
different in each species and so conspicuous, that it seems probable
that the peculiarities in length, twist, and curvature have been
differentiated for the purpose of recognition, rather than for any
speciality of defence in species whose general habits are so similar.

[Illustration: FIG. 18.--Gazella soemmerringi.]

It is interesting to note that these markings for recognition are very
slightly developed in the antelopes of the woods and marshes. Thus, the
grys-bok is nearly uniform in colour, except the long black-tipped ears;
and it frequents the wooded mountains. The duyker-bok and the rhoode-bok
are wary bush-haunters, and have no marks but the small white patch
behind. The wood-haunting bosch-bok goes in pairs, and has hardly any
distinctive marks on its dusky chestnut coat, but the male alone is
horned. The large and handsome koodoo frequents brushwood, and its
vertical white stripes are no doubt protective, while its magnificent
spiral horns afford easy recognition. The eland, which is an inhabitant
of the open country, is uniformly coloured, being sufficiently
recognisable by its large size and distinctive form; but the Derbyan
eland is a forest animal, and has a protectively striped coat. In like
manner, the fine Speke's antelope, which lives entirely in the swamps
and among reeds, has pale vertical stripes on the sides (protective),
with white markings on face and breast for recognition. An inspection of
the figures of antelopes and other animals in Wood's _Natural History_,
or in other illustrated works, will give a better idea of the
peculiarities of recognition markings than any amount of description.

Other examples of such coloration are to be seen in the dusky tints of
the musk-sheep and the reindeer, to whom recognition at a distance on
the snowy plains is of more importance than concealment from their few
enemies. The conspicuous stripes and bands