Each part of the hen's oviduct possesses to some extent, the properties of secretion and. moti- lity. Those secretions of the oviduct which contri bute to egg formation have been studied by several authors but the mechanics of egg formation have so far received little attention. The oviduct may be considered to show two types of movement: relatively slow, propulsive movements by means of which the egg is moved as far as the uterus, and relatively quick, expulsive movements which constitute the process of oviposition. The object of this work is to describe some aspects of the physiology of these latter movements, to suggest possible ways in which they are controlled and to compare them with similar movements observed during mammalian parturition.