#gastrula  double-walled stage of the embryo succeeding the blastula; the outer layer of cells is the ectoderm and the inner layer differentiates into the mesoderm and endoderm
  supertype:  conceptus__conceptu__embryo__fertilized_egg  an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval life
  part:  archenteron  central cavity of the gastrula; becomes the intestinal or digestive cavity
     part:  blastopore  the opening into the archenteron

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