AGNANO, LAGO DI, a crater lake, 5 m. W. of Naples, Italy; 4 m. in circumference, not mentioned in antiquity, probably formed in the Middle Ages, drained in 1866. It has a large modern thermal establishment with springs, natural sulphurous vapour baths and a grotto with constant exudation of warm car bonic-acid gas from the floor. There are extensive Roman re mains (V. Macchioro, Monumenti dei Lincei, xxi. p. 225. sqq., 191 1) . On the north side of the crater is a racecourse.