A paleontologist and expert in Cretaceous and Tertiary invertebrates, William More Gabb was hired by the Costa Rican government to conduct of natural historical and ethnographic survey from 1873-1875. Read before the American Philosophical Society on August 20, 1875, Gabb's essay "On the Indian tribes and languages of Costa Rica" was published in full in the APS Proceedings 14 (1875): 483-602. Dealing with several tribes, including the Bribri, the paper touches on physical description, history, the names of tribes, their political organization, and ethnography. The essay includes a brief grammar of the Bribri language.