. Canaries, hybrids, and British birds in cage and aviary. 32 CANARIES, HYBRIDS, AND BRITISH BIRDS III the first cross (P",) all the young are dark-eyed and heterozygous, d being dominant and p recessive. WTien these young are interbred, the proportions ob- tained are 3 dark-eyed to 1 pink-eyed, 3 to 1, 75 per cent, to 25 per cent. (Group IV., 2, 3, 4). The 3 dark-eyed on being tested are found to consist of 1 pure dark, and 2 impure dark, so that the composition "X=>. SILVER-GREY STARLING. Exhibttcd at the Crystal I'alace, I'JIO. by Mr. P. Walih. (.See footnote p. 23.) of F^, is
. Canaries, hybrids, and British birds in cage and aviary. 32 CANARIES, HYBRIDS, AND BRITISH BIRDS III the first cross (P",) all the young are dark-eyed and heterozygous, d being dominant and p recessive. WTien these young are interbred, the proportions ob- tained are 3 dark-eyed to 1 pink-eyed, 3 to 1, 75 per cent, to 25 per cent. (Group IV., 2, 3, 4). The 3 dark-eyed on being tested are found to consist of 1 pure dark, and 2 impure dark, so that the composition "X=>. SILVER-GREY STARLING. Exhibttcd at the Crystal I'alace, I'JIO. by Mr. P. Walih. (.See footnote p. 23.) of F^, is Id + 2 (d) 4- 1 ]>, or 25 per cent., 50 per cent., 25 per cent., the typical Mendelian proportion. Of these the d breed pure, and the p breed pure, but from the 2 (d) the same proportions are again obtained, viz., Id -I- 2(d) + Ip. The in- heritance of eye colour, however, docs not behave throughout in sinijiie Mendelian fashion, being coni])li('alcd with the ques- tion of as already explained in con- nection witli ciimanion inheritance. In order to cx])lain on iNIcndclian lines the results of the reciprocal mating to that already given, viz., pink-eyed male x dark-eyed female, it is necessary to refer to the interesting parallel ease in the Currant Moth {Abraxas grossulariata) given by Doncaster in Report IV. to the Evolu- tion Committee of the Royal Society, where the explanation of Bateson and Punnett with regard to this mating is given. They suppose that (1) femaleness is dominant; (2) that female individuals are heterozygous in respect of sex, having the constitution $ $, and producing male- bearing and female-bearing eggs in equal numbers ; and that males are homozygous, of constitution $ $ producing only male- bearing spermatozoa; (3) that there is a gametic repulsion between femaleness and the dark-eyed character. The following table gives their ex- planation of this mating of homozygous pink-eyed male heterozygous dark-eyed female Canary :— Parents. Constitu-
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