Abstract
Four kinds of North American glass lizards are recognized; Ophisaurus ventralis, O. compressus, O. a. attenuatus, and O. a. longicaudus. The various forms are discussed and compared as to coloration, scutellation, size and proportions, variability, and life history. A hypothetical history of glass lizards in North America is presented, and the relationships of the several forms are discussed. The paper concludes with some speculations on the origin of the genus Ophisaurus.