N'ime sponges, blastula larvae na-egwu mmiri gaa ebe ọhụrụ, na-ejikọta na seabed, ma na-etolite n'ime a ọhụrụ sponge. N'ọtụtụ ìgwè ndị ọzọ, blastula na-enwe mgbagwoju anya rearrangement. Ọ na-ebu ụzọ invaginates na-etolite a gastrula na a digestive ulo na abụọ iche iche germ n'ígwé, ihe mpụga ectoderm na esịtidem endoderm. N'ọtụtụ ọnọdụ, a atọ germ oyi akwa, mesoderm, nakwa n'etiti ha. Ndị a na-etolite zygotes, nke na-etolite site na mitosis n'ime a oghere oghere, a na-akpọ a blastula.
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