EVOLUTION, HEREDITY, EUGENICS 537 



Crew, F. A. E. 1923. Studies in intersexuality. I. A peculiar type 

 of developmental intersexuality in the male of the domesticated 

 mammals. Proc. Roy. Soc, B, vol. 95, pp. 90-109. II. Sex reversal 

 in the fowl. Proc. Roy. Soc, B, vol. 95, pp. 256-278. 



DoMM, L. V. 1927. New experiments on ovariotomy and the problem 

 of sex inversion in the fowl. Jour. Exp. Zool., vol. 48, pp. 31-174. 



Hartman, C. G. 1920. The free-martin and its reciprocal in the 

 opossum, man, dog. Science, n. s., vol. 52, pp. 469-471. 



LiLLiE, F. R. 1917. The free-martin: a study of the action of sex 

 hormones. Jour. Exp. Zool., vol. 23. 



LiLLiE, F. R. 1923. Supplementary notes on twins in cattle. Biol. 

 Bull., vol. 44, pp. 47-78. 



WiLLiER, B. H. 1 920. Structures and homologies of free-martin gonads. 

 Jour. Exp. Zool., vol. 23y PP- 63-127. 



Hen-Feathering in the Seabright Bantam. — We have elsewhere 

 referred (see p. 444, Internal Secretions) to the work of Goodale and 

 others in removing the ovary from the fowl, with the result that 

 the bird took on the plumage and the behavior of the cockerel. 

 T. H. Morgan, having observed that the cockerel of the Seabright 

 bantam is normally hen-feathered, performed experiments (1915) 

 which he thought furnished sufficient evidence that hen-feathering 

 in the male was due to endocrine action from luteal cells in the 

 testes. Roxas showed (1926) by cross transplantation of the testes 

 of Seabright and Leghorn fowls that no special hormones are pro- 

 duced by the hen-feathered Seabright bantam, as the soma of the 

 Seabright bantam reacts to either the male or the female hormone 

 by hen-feathering. Domm (1927) ovariotomized Leghorn fowls, 

 and noted that a compensatory testis-Iike organ developed on the 

 right side, but that subsequently the plumage became hen-like. 

 This state resembled that of the Seabright bantam, in which the 

 sexually male bird is hen-feathered. Riddle (Anat. Rec, 1925, vol. 

 30, pp. 365-384) had previously shown that when the ovary was 

 removed in the bird testicular tissue developed. 



Danforth (1928), having made exchange grafts between hen- 

 feathered and cock-feathered male bantams, has shown that the 

 differential factor is inherent in the skin. 



References on Hen-Feathering 



Danforth, C. H. 1928. Proc. Soc. Exp. Biol, and Med., vol. 26, p, 86. 

 Domm, L. V. 1927. Jour. Exp. Zool., vol. 48, pp. 31-174, 



