interesting observations have been made in more recent times. Thus Selous,
a careful bird-watcher, finds that the ruff, the male of the _Machetes
pugnax_, suffers from sexual repression owing to the coyness of the female
(the reeve), and consequently the males often resort to homosexual
intercourse. It is still more remarkable that the reeves also, even in the
presence of the males, will court each other and have intercourse.[8] We
may associate this with the high erotic development of birds, the
difficulty with which tumescence seems to occur in them, and their long
courtships.

Among the higher animals, again, female monkeys, even when grown up (as
Moll was informed), behave in a sexual way to each other, though it is
difficult to say how far this is merely in play. Dr. Seitz, Director of
the Frankfurt Zooelogical Garden, gave Moll a record of his own careful
observations of homosexual phenomena among the males and females of
various animals confined in the Garden (_Antelope cervicapra, Bos Indicus,
Capra hircus, Ovis steatopyga_).[9] In all such cases we are not concerned
with sexual inversion, but merely with the accidental turning of the
sexual instinct into an abnormal channel, the instinct being called out
by an approximate substitute, or even by diffused emotional excitement, in
the absence of the normal object.

It is probable, however, that cases of true sexual inversion--in which
gratification is preferably sought in the same sex--may be found among
animals, although observations have rarely been made or recorded. It has
been found by Muccioli, an Italian authority on pigeons, that among
Belgian carrier-pigeons inverted practices may occur, even in the presence
of many of the other sex.[10] This seems to be true inversion, though we
are not told whether these birds were also attracted toward the opposite
sex. The birds of this family appear to be specially liable to sexual
perversion. Thus M.J. Bailly-Maitre, a breeder of great knowledge and a
keen observer, wrote to Girard that "they are strange creatures in their
manners and customs and are apt to elude the most persistent observer. No
animal is more depraved. Mating between males, and still more frequently
between females, often occurs at an early age: up to the second year. I
have had several pairs of pigeons formed by subjects of the same sex who
for many months behaved as if the mating were natural. In some cases this
had taken place among young birds o