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

Thus, in Fishes, the first changes consist in the segmentation of the vitellus and the formation of a germ, processes which are common to all classes of animals.

From Facts and Arguments for Darwin by Fritz Muller

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

This vitellus or yolk undergoes a series of segmentation or dividings which are known as spontaneous segmentation.

From What a Young Husband Ought to Know by Sylvanus Stall

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