#chorion  outermost membranous sac enclosing the embryo in higher vertebrates (reptiles; birds; mammals)
  supertype:  sac  a structure resembling a bag in an animal
  part:  chorionic_villus
  part of:  fetal_membrane__fetalmembrane  any membrane that functions for the protection or nourishment of respiration or excretion of a developing fetus

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