Bull Frog, any frog which croaks with a deep rather than a sharp sound. A species of frog found in Carolina and the parts adjacent, which has a voice not unlike that of a bull. It is six or eight inches long, by three or four broad, without the legs. It swallows ducks and young goslings whole. It is difficult to catch from the length of its leap, besides which it is generally left unharmed because it is said to purify rather than to pollute the water in which it lives.
Entry from Everybody's Cyclopedia, 1912.