The Structure of the Harderian Gland of the Guinea Fowl at Embryonic and Post Embryonic Stages

The Harderian gland of the guinea fowl is a bright, pink and relatively large orbital organ situated at the ventromedial aspect of the orbit. It possesses a single duct that has its exit on the convex medial surface. The outline is irregular with its caudal half narrower than the rostral half, and possessing a slight constriction about the mid point. Histologically, the gland had been outlined with the existence of a large contorted lumen by day 18 of incubation. The surface epithelial lining showed two layers of cells all through and lymphocytes were also present. By day 19 of incubation, certain zones of the surface epithelium had become pseudostratified and some of these cells contained vacuoles indicative of secretory materials within their cytoplasm. By day 21, few definitive acini with lumina had been observed and at day 23, the epithelium had assumed only a single layer of cells that were tall columnar cells, except at the junctions of the folds. By day 24, the tunica propria seemed to have completely disappeared with the acini occupying every available space. Plasma cells were seen three days after hatching.