A scanning electron microscopic study of the oviduct of the toad, before and during ovulation

The surface features of the oviduct of the toad, Bufo melanostictus, was studied under the scanning electron microscope. The epithelial folds show regional variations, being longitudinally disposed in the upper part of the oviduct, spirally arranged in the middle and convoluted in the lower part. There is an abundance of cilia through the oviduct except in the ovisac. Goblet cells are interspersed among the epithelial cells. In between the epithelial folds are openings of tubular secretory glands. During ovulation, there is patchy loss of cilia throughout the oviduct. Most of the goblet cells are empty. On the surface, the cilia are matted together by secretory material which are laid down in layers.