herings,
we shall come, I fancy, to no other conclusion than that much loss of
valuable time and needless waste of energy would often be incurred in
the search, and that many an individual would fail to breed just because
its wanderings took it into districts in which, at the time, there
happened to be too many of this sex or too few of that. And as the power
of locomotion increased and the distribution of the sexes became more
and more irregular, so the opportunity would be afforded for the
development of any variation which would have tended to facilitate the
process of pairing, and by so doing have conferred upon the individuals
possessing it, some slight advantage over their fellows.

What would have been the most likely direction for variation to have
taken? Any restriction upon the freedom of movement of both sexes would
only have added to the difficulties of mating; but if restriction had
been imposed upon one sex, whilst the other had been left free to
wander, some order would have been introduced into the process. That the
territory serves to restrict the movements of the males and to
distribute them uniformly throughout all suitable localities, there can
be no question; and since the instinctive behaviour in relation to it is
timed to appear at a very early stage in the seasonal sexual process,
the males are in a position to receive mates before the impulse to mate
begins to assert itself in the female.

We will take the Ruff as an example. According to Mr. Edmund Selous,
pairing, in this species, is promiscuous--the Ruffs are polygamous, the
Reeves polyandrous. Suppose, then, that upon this island of some few
miles in circumference, whereon his investigations were made, the
movements of neither Ruff nor Reeve were subject to control, that the
birds wandered in all directions, and that the union of the sexes were
fortuitous, would the result have been satisfactory? We must remember
that the Reeve requires more than one Ruff to satisfy her sexual
instinct; we must also bear in mind the possibility that the functioning
of her instinct may be subject to some periodicity, and we ask whether,
under these circumstances, accidental gatherings would meet all the
requirements of the situation. Now, manifestly, she must be in a
position to find males when her appropriate organic condition arises.
But in the absence of any system in the distribution of the sexes, how
could delay be avoided, or how could a uniform discha