フナ(Carassius auratus)の間性と中性

概要

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It is known that the sex ratio in certain varieties of the crucian (the Funa, Carassius auratus (L.)) is aberrant, female being strikingly predominant over male. In the course of the histological study of gonads on the one year's old "Funa", the author found two intersexes and six neuters out of total two hundred cases. In two races of the Japanese crucian, Marubuna and Hirabuna, two and four were neuters respectively, having neither testis nor ovary. The gonadal tissue of these neuters were thread-like form of milky color and was filled up with degenerated testicular-like cysts (Fig. 3). As shown in Fig. 2, the "ova" found in the intersexual gonads of the two specimens can be regarded as genuine ova. That is, some of these ovea were about the normal size of matured eggs, and were surrounded by follicle cells and egg membrane, and well-defined yolk. The ova coexisted with the testicular tissue in the middle part of the gonad, whereas the posterior region was occupied by the ova only.
1959-11-15