The rest of the egg provides both nourishment and protective housing for the germ cell. Its construction takes about 25 hours and begins when the ovary releases the completed yolk. The yolk is then gripped by the funnel-shaped opening of the oviduct, a tube 2–3 feet/0.6–0.9 meter long. If the hen has mated in recent days, there will be sperm stored in a “nest” at the upper end of the oviduct, and one will fuse with the egg cell. Fertilized or not—and most eggs are not—the yolk spends two to three hours slowly passing down the upper end of the oviduct. Protein-secreting cells in the oviduct lining add a thickening layer to its membrane, and then coat it with about half the final volume of the egg white, or albumen (from the Latin albus, meaning “white”). They apply this portion of albumen in four layers that are alternately thick and thin in consistency.