Studies on the sterility in hybrid birds.

Abstract

The reproductive organs of four hybrids belonging to the Family Ploceida, (Ayes) mentioned below were studied from the histological viewpoint. These hybrids were considered in their life time to be sterile, and their exceedingly incomplete gonads proved it right.(1) Padda oryzivora × Lonchura striata var. domestica.Two females were examined. The ovaries were degenerated to a small gland-like body, consisting of a few abortive follicles among the connective-tissue (Figs. 1 and 5). The oviducts were also very incomplete in structure (Figs. 2, 3, 6 and 7). In one of the females the secretory glands were entirely absent in the wall of the duct.(2) Lonchura atricapilla × Lonchura striata var. domestica.One female was examined. The ovary and oviduct were degenerated far more than in the aforementioned, and the end of the Fallopian tube was closed (cf. Figs. 8-11).(3) Erythura trichroa × Erythura psittacea.One female was examined. In this case the ovary could not be found. The oviduct was also very incomplete, and the glands and muscles were not to be seen in its wall, though the end of the Fallopian tube was not closed (cf. Figs. 12-13).(4) Aidemosyne modesta × Aidemosyne malabarica.One male was examined. The seminiferous tubules were observed in the testes which were nearly normal in size (Figs. 14-16). In the majority of tubules there ranged only Sertoly's cells, but no germ cells (cf. Figs. 15-16). The interstitial cells were, on the contrary, much developed among the tubules (Fig. 16).