blas·to·sphere /ˈblæstəsˌfɪ(ə)r/ 名詞
  囊胚,囊胚泡
  Blas·to·sphere n.  Biol. The hollow globe or sphere formed by the arrangement of the blastomeres on the periphery of an impregnated ovum.
  Note: [See Illust. of Invagination.]
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  blastosphere
       n : the blastula of mammals [syn: blastocyst]