Cytoarchitectural and surface ultrastructural analysis of the olfactory epithelium of Oreochromis nilotica (Linnaeus).

The olfactory organ of Oreochromis nilotica was studied by means of light and scanning electron microscopes. The oval shaped olfactory apparatus consists of 19-20 lamellae radiating from a central raphe. The receptor epithelium occupies the restricted area of the middle swollen region of the lamellae and is framed with receptor cells (both ciliated and microvillous) and rod cells. The larger part of the lateral surface of the olfactory lamella is covered with non-receptor epithelium, which is made up of stratified epithelial cells and mucous cells. The functional significance of various cells lining the olfactory epithelium of this fish are discussed.