The Mexicans possessed a small whistle formed of baked clay, a considerable number of which have been found. Some specimens are singularly grotesque in shape, representing caricatures of the human face and figure, birds, beasts, and flowers. Some were provided at the top with a finger-hole which, when closed, altered the pitch of the sound, so that two different tones were producible on the instrument. Others had a little ball of baked clay lying loose inside the air-chamber. When the instrument was blown the current of air set the ball in a vibrating motion, thereby causing a shrill and whirring sound.