The «Gruta das Onças», a cave situated in the Caatinga do Moura district, municipulity of Jacobina, Bahia State, has been a rich source of fossils (Cartelle & Bohórquez, 1982 and Cartelle, 1983). In this same fóssil bed we have found large quantities of skeletal pieces of Eremotherium laurillardi (Lund, 1842), together voith Nothrotherium maquinense Lydekker, 1889, Smilodon populator populator Lund, 1842 and a series of skeletal pieces of the giant armadillo vohich is the object of our present study. In this study we have given special emphasis to the cranium; a comparative study of related species, especially Pampatherium humboldti (Lund), 1839, is made.