ULTRASTRUCTURAL AND HISTOCHEMICAL-CHARACTERISTICS OF THE LATERAL OVIDUCTS OF BACULUM-THAII HAUS (PHASM)

The wall of the lateral oviducts of Baculum thaii is composed of a mon olayered epithelium, lacking a cuticular intima, which lies on a sheat h of striated muscular fibres. Untreated oviductal specimens exhibit t wo distinct regions. The anterior region, into which the various ovari oles emerge, is opalescent. The posterior region is more dilated and d arker in colour. On the basis of the ultrastructural characteristics o f the epithelial cells, four successive zones are definable for each o viduct. The first two zones comprise the most anterior oviductal area while the third and fourth comprise the posterior region. In zone 1 on ly is the oviductal wall composed of a single cell type. In addition, differences in structural organization between mated and virgin female s were observed in this zone alone. In the three remaining zones, two distinct cell types were distinguishable according to two models of fu ndamental organization: cells having numerous apical microvilli and do me-shaped cells. The results of histochemical analyses established tha t the abundant secretory product elaborated by the epithelial cells is rich in both proteins and predominantly acidic mucosubstances. The hi stochemical characteristics of the secretory product differentiate sig nificantly not only between the four zones in the same individual but also when the corresponding zones are compared in the mated and virgin females.