羊膜[包圍胎兒的膜]
Amnion \Am"ni*on\, n. [Gr. ? the membrane round the fetus, dim. of ? lamb.] (Anat.) A thin membrane surrounding the embryos of mammals, birds, and reptiles.
amnion n : thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals) [syn: {amniotic sac}, {amnios}] [also: {amnia} (pl)]