Within the epithelium of the head gut of the sword-tail (Xiphophorus helleri Heckel) there are three types of taste buds that can be identified with certainty in the scanning electron microscope. The breathing valves, which are situated behind the mouth region, bear relatively high epidermal papillae in which type I taste buds can be found. The middle region of the head gut is mostly occupied by low epidermal papillae containing type II taste buds. Type III taste buds are present within the metabranchial head gut; they never rise above the normal level of the epithelium. Taste buds of each type show two kinds of receptor villi within their receptor areas: tall villi (about 1,5×0,5 m) and small villi (about 0.5×0.2 m). A few tall villi belonging to solitary chemosensory cells are situated between the superficial epithelial cells of the tongue. In addition, the surface of the epidermal cells shows a delicate microridge system.—It is postulated that the taste buds of different types serve different functions: Taste buds within epidermal papillae may act both as chemoreceptors, and mechanoreceptors. Taste buds that never rise above the normal level of the epithelium perhaps act predominantly as chemoreceptors.