zo·na pel·lu·ci·da /ˌzonəpəˈlusədə, pɛlˈju-/
  zona pel·lu·ci·da /-pəˈlusədə/ 名詞
  (拉)透明帶
  Zo·na n.; pl. Zonae   A zone or band; a layer.
  Zona pellucida. 
  Zona radiata 
  ◄ ►
  zona pellucida
       n : thick membrane around the mammalian ovum; can be penetrated
           by one sperm in the fertilization process; usually
           remains around the fertilized egg until it is implanted
           in the wall of the uterus