or CAYSTRUS, in Ancient Geography, a river of Ionia, the embouchure of which Ptolemy places between Colophon and Ephesus. It is commended by the poets for its swans, which it had in great numbers. Its source was in the Montes Ciblani. After many windings through the plains of Ephesus, it becomes deeper, and flows smoothly into the sea near that city. At the foot of Mount Gallesus it is crossed by an ordinary bridge of three arches. It is sometimes called by the Turks Little Meendras, after the river Meander, which it resembles in its windings. Caijstrius Campus was part of the territory of Ephesus. The Campi Caijstriani of Lydia were plains lying in the middle between the inland parts and Mount Tmolus.