イトマキヒトデの皺胞胚

概要

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The occurrence of wrinkled blastula stage was ascertained in the early development of Asterina pectinifera (MULLER et TROSCHEL). Five hoursafter the insemination, the stage at 20-22℃. The blastulae had a large central blastocoel surrounded by a single layer of blastomeres of equal size. Thirty minutes thereafter, egression tracts appeared on the surgace of the blastulae. These were due to multipolar invaginations of the blaseoderm. They did not represent true gastrulation but showed so-called wrinkled blastula formation. Then these invaginations became deeper and reached to the center of the blastocoel. Five hours after the beginning of wrinkling, the surface of the blastulae resumed smoothness by the fusion of neighboring egression tracts. As a result of this process the blastoderm became multilayered, at least in part. Eleven hours after the insemination true gastrulation took place, and early gastrulae hatched out 30 minutes thereafter. Since the embryos which passed through the wrinkled blastula stage developed into typical bipinnaria larvae, the wrinkled blastula stage seems to be a stage inevitable in the normal course of development of Asterina pectinifera.
社団法人日本動物学会の論文
1972-09-25