Auricula, a genus, and Auriculidæ, a family of Gasteropod Mollusca (Lat. auricula, 'a little ear'). They have a spiral shell, covered with a horny epidermis, the first whorl very large and the spire short, the lip elongated, thickened, and toothed. The respiratory organ, or 'lung,' is a space below the mantle, on the walls of which the blood is exposed to the freely admitted air. They thus belong to the Pulmonate order of Gasteropods—i.e. to the same order as the common snails, having respiratory organs adapted for breathing in air, though some of them are capable of subsisting for a considerable time in water. Some inhabit fresh-water marshes, while others prefer the vicinity of salt water. They generally belong to warm climates, and some of them attain a large size. Auricula midae, a native of the East Indies, is known to shell-collectors by the name of Midas's Ear.