The male oyster must be inferior, therefore, in organisation to the female. Its constitutional potential is less, since the constitutional potential of the female contains both its own, and the potential of the male. And the lesser, it is admitted, cannot contain the greater; although higher evolutionary forms, when subjected to conditions which preclude them from sustaining these their higher forms, may lapse to modes less complex. Further and more striking examples of such Sex-transformation are afforded by so-called "mules," or "neuters," which occur in other species. A well-known case is that of a pea-hen belonging to Lady Tynte. Having laid eggs from which chicks were raised, this pea-hen, after moulting, developed feathers proper to the other sex; appearing like a pied peacock. In the third year the same phenomenon occurred in her; she developed spurs, moreover, resembling those of the cock. _She never bred after this change in her plumage._ As already mentioned, kindred phenomena of sex-metamorphosis are observed in women after operations involving removal of reproductive glands. That the female is, indeed, a more complex order of organisation than the male, is not to be doubted, since masculine characteristics emerge from it when it lapses from its normal of condition. Adolescence as it occurs in the boy and in the girl emphasises this conclusion. To the age of twelve or thereabouts, the normal boy- and girl-child are like enough to one another; smooth-skinned, active, simple creatures. The boy is, normally, larger, sturdier, stronger and rougher than the girl. But, save for the cut of their hair and of their clothes, the two are very similar. With the transition to manhood and womanhood, respectively, notable differences accrue, however. From having been a strong, young, active, boy-like creature, now--provided her development be allowed to take the normal course--the girl loses physical activity and strength. A phase of invalidation sets in. Instinctively, she no longer runs and romps. New languors invest her in mind and in body. She is indisposed to brain-work or to much exertion. She lounges and muses. Her mind is clouded with the mists of awakening sensibilities. She suffers from lassitudes. She becomes a complex of disabilities, indeed; disabilities which in delicate, sickly or over-taxed girls, show in chlorosis, anæmia, hysteria and other ills. Obviously, profound changes, with re-adjustments of her constitutional resources, are taking place in her. And most significant of these is that which shows like an _arrest_ of development, physical and intellectual. Because, normally, she develops but little further along direct lines of intellect and muscle. Yet that she is still developing, and this upon wholly new--subtler, higher and more complex lines, is manifest at the end of this transition-period whence she emerges, a woman.