The Ciliary Systems in the Oviduct of the Pigeon. ∗

Abstract

Over a year ago I described the ciliary systems in the oviducts of the painted turtle. 1 , 2 These ducts are lined from the infundibulum to the distal outlet with ciliated epithelium. In the proximal portion of the ducts the cilia form two systems, a general one, the abovarian, which sweeps from the ovary toward the exterior and which covers most of the inner surface of the duct, and a restricted one, the pro-ovarian, a narrow longitudinal band not more than 2 mm. wide, in which the cilia beat toward the ovary. As was pointed out in these earlier publications, the spermatozoa can make no headway against either of these systems but are swept up or down the duct in accordance with the system with which they are associated. It is clear from the action of these cilia that the pro-ovarian system must be concerned with the transportation of the sperm cells to the ovary and the abovarian with the clearing of the oviducts and possibly with the transportation of the eggs toward the exterior. It is a matter of interest to ascertain to what extent these two systems are represented in the birds and in the mammals.

The oviduct of the pigeon was studied with this question in mind. It is comparatively easy in this oviduct to distinguish the 5 conventional parts, namely, the infundibulum next the ovary, the extensive albumen-producing portion of the duct, the somewhat restricted isthmus, the so-called uterus or shell-producing part, and, at the distal end, the vagina. All these parts in the pigeon as in the turtle are covered with a ciliated epithelium whose cilia for the most part beat from the interior toward the exterior.