Abstract
Developing germ cells from oogonia to oocyte stages in embryonic quai1 ovaries were observed ultrastructurally. in contrast with those of chicks, quail oocytes showed some conspicuous structures. Typical feature of the Balbiani body, which was constructed by eccentrical concentration of whole organelles, was observed through the oocyte stage, although loose aggregations of organelles were found even at the oogonial stage. Such striking feature of Balbiani body was not observed as yet in any animal species. Golgi apparatus, which occupied the center of a Balbiani body, was often found attaching with the nuclear membrane. This finding suggests that the Balbiani body playsome role for the oocyte maturation.
Upon the nuclear membrane of oocytes, a great number of electron dense structures were found. They were thought to be a kind of nuclear pore complexes. Such abundance of the nuclear pore complexes was another structural characteristic of quai1 oocytes. They increased in number according to the progress of embryonic development, although smal1 numbers were also seen even at the oogonial stage.
