_Shape._—In a well-developed Plymouth Rock pullet, but one whose reproductive organs have never become active, the oviduct is about 4½ inches long; in the fully developed and active state it is from 18 to 20 inches long, and in a collapsed state about ½ inch in diameter. It is held in position by two ligaments, a dorsal and a ventral (Fig. 55, _B_) to be described later. The oviduct is tortuous in its course, forming three principle convolutions before reaching the cloaca, and like the ovarian mass, in its active state, pushes the abdominal viscera downward and toward the right side. _Structure._—The oviduct consists of three coats: first, the serous, located on the outside, which is a reflection of the peritoneum; second, the muscular middle tunic; third, the mucous coat, which in a resting state is thrown into folds. [Illustration: FIG. 59.—The active oviduct of a hen laid open. 1, The ovary. 2, The funnel. 3, The albumin-secreting portion. 4, The isthmus. 5, The shell=gland portion. 6, The vagina. 7, The superior ligament. 8, The inferior ligament. ] =Parts of the Oviduct.=—The parts of the oviduct are as follows: the funnel, the albumin-secreting portion, the isthmus, the shell-gland portion, or uterus, and the vagina (Fig. 59). [Illustration: FIG. 60.—The mucous lining of the oviduct. _A._ Transverse section of the oviduct wall in the region of the neck of the funnel showing primary and secondary folding of the epithelium (after Surface). _B._ Showing the type of gland cells of the funnel region. _C._ Transverse section through the wall of the uterus showing the deep folds. _D._ Section from the albumin-secreting portion showing the opening of a tubular gland and also showing the character of the cells. ]