yolk

(yok) (L. cvitel’lus]. 1. The nutrient part of the ovum; also the yellow portion of the egg of a bird. 2. Crude wool-fat or suint. ace sory y., the nutritive yolk; the portion of the yolk that serves for the nutrition of the formative rtion. y.-cells, y.-granules, the morphologic elements composing the yolk. y.-cleavage, segmentation of the vitellus. y.-food, the nutritive part of the yolk of an ovum: deuteroplasm. formative y., that part of the ovum whence the embryo is Vieveloped y.-sac. Same as umbilical vesicle. See tesicle. y.-skin, the titelline membrane (q. y: “space, the space formed in the ovum by the shrinking of the vitellus See lig- See tsutsugamushi dis- from the zona pellucid a. y.-stalk. Same as umbilical duct. See duct.