in marine birds and reptiles that drink saltwater, gland that extracts the salt and removes it from the animal's body. Its function was unknown until 1957, when K. Schmidt-Nielsen and coworkers solved the long-standing problem of how oceanic birds can live without fresh water. They found that a gland, located above each eye, removes sodium chloride from the blood far more efficiently than does the avian kidney and excretes it as brine through a duct into the nasal cavity. It is discharged from the nostrils (sometimes the mouth) in headshaking movements characteristic of cormorants, penguins, and other marine species. In marine reptiles a similar gland is located between eye and nostril.