The lateral nasal (salt-secreting) glands of S. demersus were found to be morphologically and histologically similar to the salt glands of marine birds in general. No significant differences were recorded in the ionic and osmotic composition of nasal and cloacal fluid that was collected at 18°C and 28°C respectively. The daily intake of 220 g of fish per bird, however, had a significant influence on the diurnal variation of the potassium values of the cloacal fluid. A very low flow-rate and high osmotic concentration of the nasal gland exudate was recorded, indicating the efficiency of the nasal glands as auxiliary osmoregulatory organs. Keywords: Ambient temperature, Cloacal fluid, Ducts, Granular plasma, Histologically, Illustrations, Inorganic ions, Iso-osmotic, lateral nasal (salt-secreting) glands, Morphologically, Muciferous excreta, Osmoregulation, Penguins, Secretory cells, Spheniscus demersus.