This is the first report of a series on Foraminifera of Brazil. The animals were collected on the Brazilian continental shelf and only the Miliolidae, Peneroplidae and Alveolinellidae were taken into consideration in this paper. Forty one species were described, belonging to the following genera: Quinqueloculina D'Orbigny, Articulina D'Orbigny, Massilina Schlumberger, Pyrgo Defrance, Pyrgoella Cushman & White, Biloculinella Wiesner, Spiroloculina d'Orbigny, Sigmoilina Schlumberger. Ilauerina d'Orbigny, Flintia Schubert, Triloculina d'Orbigny, Peneroplis Montfort, Archaias Montfort, Sorites Ehrenberg, Borelis Montfort. Two regions were established from the observation of the distribution of the Miliolidae, Peneroplidae and Alveolinellidae. The animals collected from 23º S northwards were captured in warm tropical waters and those found on Banco S. Tomé, Barra de S. João, and Trindade Island are the same which occur in the West Indies. According to Ekman (1953, p. 4) the coral regions are not always formed by animals. They may also be formed by algae belonging to the genus lÀtliothamnion. The samples I, II, and III were collected in such coral formations. The following species occurred from this southern limit northwards : Articulina multilocularis, A. sagra, A. sulcata, Hauerina bradyi, H. ornatissima, Quinqueloculina funafutiensis, O. tricarinata, Miliolinella oblonga, Massilina crenata, Spiroloculina antillarum, S. caduca, Triloculina planciana, Peneroplis bradyi, P. carinatus, P. pertusus, P. proteus, Archaias angulatus, Sorites marginalis and Borelis pulchra.
