SWIFT, C. H., 1914. Origin and early history of the germ cells of the chick. Amer. Jour, of Anat., XV. TANDLER, J., und K. KELLAR. Die Körperform der weiblichen Fruehkastraten des Rindes. Archiv Entw-mech., XXXI. --------, und S. GROSZ, 1909, 1910. Ueber den Einfluss der Castration auf den Organismus. Archiv f. Entw-mech., XXVII, XXIX, XXX, 1909. --------, und S. GROSZ, 1913. Die biologischen Grundlagen der sekundären Geschlechtscharaktere. Berlin. V. LA VALETTE ST. GEORGE, 1895. Zwitterbildung beim kleinen Wassermolch. Arch. Mik. Anat., XLV. WALKER, C. E., 1908. The influence of the testis upon the secondary sexual characters of fowls. Proc. Royal Soc. of Med. WALLACE, A. R., 1891. Darwinism: An exposition of the theory of natural selection. London. --------, 1891. Natural selection and tropical nature. London. WEBER, M., 1890. Über einen Fall von Hermaphroditismus bei _Fringilla coelebs_, Zool. Anz., XIII. YARRELL, W., 1827. On the changes in the plumage of some hen-pheasants, Phil. Trans., 117. --------, 1857. On the influence of the sexual organ in modifying external character. Journ. Proc. Linn. Soc., I. DESCRIPTION OF PLATES. PLATE 1. FIG. 1. Black-Breasted Game bantam cock. He is typically cock-feathered, but, as in all games, his hackles and tail-coverts are shorter than in the cocks of other breeds. The comb was dubbed by the breeder. FIG. 2. Black-Breasted Game bantam hen. The great contrast in color between the cock and hen is practically the same as that in the Brown Leghorn, in most races of Tosa fowls, and in the wild type _Gallus bankiva_. FIG. 3. Sebright cock, “hen-feathered.” The short hackles, the rounded feathers of the back and saddle, and the shortness of the tail-coverts are characteristic features of these males. For details of individual feathers from different regions see plates 6 and 8. FIG. 4. A castrated Sebright male. The drawing was made about a year after the operation. This particular bird developed a lighter color than did other castrated Sebrights (see plate 3, fig. 1). The entire dorsal region has changed its color, and the feathers have also changed in shape, length, etc. Note especially the very long hackle and saddle feathers (for details see plate 6, fig. 1_a_) and the change in the wing-bow. The tail-coverts have also grown long. PLATE 2. FIG. 1. F₁ hen-feathered male out of Game by Sebright. The hen-feathering in this bird is as complete as in the Sebright. FIG. 2. F₁ female out of Game by Sebright.