#blastocoel__blastocoele__blastocele__segmentation_cavity__cleavage_cavity  the fluid-filled cavity inside a blastula
  supertype:  bodily_cavity__cavity__cavum  (anatomy) a natural hollow or sinus within the body
  part of:  blastula__blastodermic_vesicle  early stage of an embryo produced by cleavage of an ovum; a liquid-filled sphere whose wall is composed of a single layer of cells; during this stage (about eight days after fertilization) implantation in the wall of the uterus occurs

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