zona-radiatahttp://www.oed.com/dictionary/zona-radiata_n%3Ftab%3Dmeaning_and_usezona radiata, n.
First published 1921; not fully revised

zona radiatanoun

  1. 1881–
    A radially striated form of the zona pellucida surrounding the ova of certain vertebrates as seen in the light microscope.
    1. 1881
      The ovum [of Teleosei] when laid is usually invested in the zona radiata only.
      F. M. Balfour, Treatise on Comparative Embryology vol. II. iv. 55
    2. 1925
      The zona radiata of the vertebrate ovum, conspicuously shown in the fishes, is a thick and often double membrane traversed by fine radial canals.
      E. B. Wilson, Cell (ed. 3) iv. 272
    3. 1964
      The ovum [of Salmo trutta, the brown trout] is covered by a thick membrane, the zona radiata.
      T. J. Parker & W. A. Haswell, Text-book of Zoology (ed. 7) vol. II. 319

Originally published as part of the entry for zona, n.

zona, n. was first published in 1921; not fully revised.