The ovum and its coverings. The corona radiata, which completely surrounds the ovum, is only represented in the lower part of the figure. Labels: 1, corona radiate; 2, granular layer; 3, vitelline membrane; 4, zona pellucida (oolemma); 5, vitellus or yolk; 6, germinal vesicle (nucleus); 7, germinal spot (nucleolus); 8, nuclear membrane.
Cunningham, D.J. Textbook of Anatomy (New York, NY: William Wood and Co., 1903)