The first record of occurrence of Myriastra purpurea (Ridley, 1884) for the South Atlantic Ocean at shallow areas of the Brazilian coast (State of Rio de Janeiro, Sepetiba Bay: 23º04'53"/44º00'34"W and State of Santa Catarina, Porto Belo: 27º09'12"S/48º29'30"W) widely enlarges the distribution of the species, known only from the Indo-Pacific region. Detailed descriptions and ilustrations of the specimens are offered. A table of micrometric measurements and camera lucida drawings of spicules is also offered.

É descrita no presente trabalho uma serie de esponjas tetraxonidas, co letadas no Atlântico Sul entre Cidreira e Sarita, pelo N/Oc. "Prof. W. Besnard", durante o período de junho a dezembro de 1968, com dados sobre a salinidade e a temperatura dos pontos de coleta, bem como sobre a distribuição geográfica e batimêtrica dos exemplares estudados.

Six species of tetraxonid sponges occurring in southern Brazil are studied: Jaspis johnstoni (Schmidt, 1862); Geodia eosaster (Sollas, 1888); Erylus oxyaster Lendenfeld, 1910; Pachastrella monilifera Schmidt, 1868; Sphinctrella cribrifera (Sollas, 1886) and Coscinospongia typus (Schmidt, 1870) . Data are also given on the temperature and salinity for the oceanographie stations where the specimens were collected in the South Atlantic coast at Rio Grande do Sul (Lat. 30º60'S - 33º29'S and Long. 49º13'W - 50º44'W). The collections were made by R/V. "Prof . W. Besnard", from 150-284 m depth, during the period of June to December, 1968. All species are recorded for the first time for the coast of Rio Grande do Sul. Morphological characteristics and spicular structure of the specimens are described and illustrated. Spicular measures are also given for the material studied.