hydra can, without the aid of another, "bud off" a new living hydra. Bisexuality is evidenced, however, in the presence of male and female cells which form in the single hydra. These unite with one another to produce a new individual in true bisexual manner. In a sense this creature is a combination of the autosexual, bisexual and hermaphrodite.
Another step up the evolutionary ladder we find the earthworm. Each worm has the organs of the two sexes—the equivalent of testes and ovaries,—properly developed, but each worm needs another worm to induce fertilization. In this instance, we have true hermaphroditism, and bisexuality is definitely established. However, as the two worms are of the same sex—each being male as well as female—they are in that way homosexual, as well, being attracted by worms of similar constitution.
As life grows more complex and we ascend the biological scale, the sexual processes also become more ramified, until in the higher forms of life we find the sexual nature of the individuals of the different genera and species sharply differentiated.
But even in the highest form of life, there are the vestigal organs and characters of the opposite sex, so that while the normal human being has a definite sexual category, it is just as truly apparent that no individual is wholly of one sexual character. The most masculine man is not one hundred per cent masculine, nor is the most feminine woman one hundred per cent feminine. The proof of this will be shown as we proceed in our discussion.
The physical bisexual characters—those of
