2 0 0 0 OA 南日本産三新鳥の記載
1 0 0 0 OA マガモ雌の所謂「雄化」4例
In Japan there have been collected only four wild specimens of what we call the Female Mallard assuming the male plumage. Among these intersex specimens, no. 2 example which came from Teganuma, Chiba Prefecture, was studied by Dr.Yamashina ('48) and was found to have had its right and left ovaries turned into testes. Concerning the remaining examples the same phenomena have been seen in the old females, such as the Mandarin Duck, the Teal and the Pintail, which must have been brought about by the shrinkage or some other disorder of their ovaries. Bluba ossea, an organ belonging to trachea, peculiar to the male duck, does not exist in these intersex specimens and proved not te be affected by means of sex hormone.