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Internally there were two oviducts, that of the left side normally developed, that of the right diminutive and less than half the full length. The gonad of the left side had the tubular structure of a testis, but showed no signs of active spermatogenesis, but in its lower part contained two ova. Camb. Univ.
Sex exhibition differs in man and woman because of the differently combined internal secretions that are their substrates. The male's attitude, aggressive pursuit, is instigated by the compound adrenal and gonad endocrines. The female's various emulsions of coyness and display are motivated by posterior pituitary and gonad hormones in alliance.
There was a fully developed oviduct on the left side, on the right another less than half the full length. There was also a vas deferens on each side. There was a gonad on each side, that of the right about one-fourth the size of that on the left. In microscopic structure the right gonad resembled a testis consisting entirely of tubuli lined by an epithelium consisting of a single layer of cells.
For example, Paton says : "The evidence thus seems conclusive that in the male the gonad, by producing an internal secretion, exercises a direct and specific influence upon the whole soma, increasing the activity of growth, moulding the whole course of development, and so modifying the metabolism of nerve and muscle that the whole character of the animal is altered."
With regard to the gonads, in this bird a single organ was found on the left side, i.e. in the position of the ovary in normal females, and there was no trace of a gonad on the right side.
Even in these cases the moth when developed showed the original characters of the sex to which belonged the caterpillar from which it came, although it was carrying a gonad of the opposite sex. It will be seen that these results are the direct opposite of those obtained by Steinach on Mammals.
With regard to the last case it is to be remarked that though the gonad on the right side was entirely male, there was no unilateral development of male characters.
And in the Bushman of South Africa, the cretin's face is even more startlingly recalled. There is every reason then for believing that the white man possesses more of pituitary, adrenal, gonad, and thyroid internal secretions as compared with the yellow man or black man.
In the first place, the term sex-linked does not mean occurring always exclusively in one sex, but the direct contrary transmitted by one sex to the opposite sex and in the second place there is no suggestion that the development of the character is dependent in any way on the presence or function of the gonad.
In one part of this organ the tubules were larger than elsewhere, and one of them exhibited spermatogenesis in progress. The left and larger gonad had a quite similar structure, but at its lower end were found two ova enclosed within a follicular epithelium.
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