vitellus

Vitelligenous: producing the vitellus or yolk: said of certain cells in the ovaries, believed to have that function.

From Explanation of Terms Used in Entomology by John. B. Smith

Yolk, yōk, Yelk, yelk, n. the yellow part of an egg: the vitellus of a seed: wool-oil.—adjs.

From Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements) by Various

Up to this point the vitellus of the egg, nourished by endosmosis through its membranes, had sufficed for the nutrition of the still very small embryo.

From The Sexual Question A Scientific, psychological, hygienic and sociological study by Auguste Forel

"The ovarian eggs of all animals are identical, small cells with vitellus, germinal vesicle and germinal spot."

From Facts and Arguments for Darwin by Fritz Muller

Within the shell the animal portion of the egg is found; which consists of a viscous, colorless liquid called albumen, or the white, and a yellow globular mass called the vitellus, or yolk.

From Donahoe's Magazine, Volume XV, No. 3 Volume XV (Jan 1886-Jul 1886) by Various