Abstract
A new silver-colored plumage mutation was found in a closed colony of the Japa-nese quail. This mutation was inherited by a simple, autosomal gene(s) recessive to the wild-type. The female homozygotes were able to ovulate, but they were unable to secrete albumen in spite of immunoelectrophoretic and histochemical evidence that their oviducal tissues contained conspicuous amounts of albumen. Reproductive performance of the homo-zygous males and heterozygotes of both sexes were judged as normal, and all the functional defects were localized upon the Miillerian duct system. Segregation of the plumage color dilution from the secretory defects in the oviduct has not been observed in the subsequent generations.