Introduction: In the summer of 1883 we published in the Proceedings of the Academy of Natural Sciences of Philadelphia, pp. 116 to 124, a ” Review of the Species of Gerres found in American Waters.” In December of the same year, Dr. Jordan made a large collection of the Atlantic species of this genus at Cedar Keys, Key West and Havana. A large portion of this collection is now in the Museum of the Indiana University, and constitutes the material upon which the present paper is based. The present collections contain numerous specimens of species not before examined by us, and, in the light of the new relationships which an examination of them discloses, we have thought it best to attempt an entire revision of the genus. We have therefore collected all the synonymy up to date, made an analytical key by which the species can be determined, and given a detailed description of all the species now before us. To the account of the Pacific Coast species, as given in the former paper, we have now nothing to add, as the very extensive collection of them studied by us has been since mostly destroyed by fire. We take this opportuinity of acknowledging our indebtedness to Dr. Jordan for the use of his library, and for other aids.
