There are a few statements in the summary of this paper that call for comment. The statement that the “development of comb, spurs, and wattles does not stand in direct quantitative relation to the sex of the gonad,” appears to be only intended as a statement of fact based on the author’s observation. But in what sense is there an expectation that they should stand in such relation beyond the obvious fact that in the cock the comb and wattles are larger than in the hen, and that spurs are generally present only on the cock. But if the expression “sex of the gonad” implies the germ-cells it is not at all certain that there is any expectation of a quantitative relation, and there is some probability at least that other cells than the sex-cells are involved in the development of combs, wattles, and possibly spurs. A castrated cock has a small comb resembling that of the female bird. On the other hand, removal of the ovary sometimes leads to an increase in the comb and wattles. Here we have, to say the least, a paradoxical situation, for the result looks superficially as though something in the ovary keeps down the hen’s comb, while something in the testes keeps up the cock’s comb, yet when the ovary is removed the hen develops a cock’s comb; when the testes are removed the cock develops a hen’s comb. The real meaning is, I think, that the genetic complex for femaleness (one Z or else ZW) stands in itself for a full-sized comb, while the genetic complex for maleness (two Z’s) stands in itself for small comb. Boring and Pearl state that “body-shape and carriage have a genetic relation to the sex of the gonad.” This statement means, I think, that the amount of testicular matter present stands in some direct relation to the shape of the body and carriage of the male. Castration, both of the normal cock and the Sebright, seems to change the carriage somewhat and perhaps the shape. Both lose something of the peculiar attitude of the male, but I have not been able to my own satisfaction to analyze what this means. As has been pointed out, and as the pictures show, the castrated Sebright changes his attitude, but whether this is a change due to his new contour, or to a new balance resulting from a large tail, or to a let-down resulting principally from effects on the nervous system, is difficult to determine. The same statements apply in part to the castrated cock of ordinary breeds, but not to the same degree, since the change after castration, in feathering and in carriage at least, is slight.