In this paper are given distributional records of species already known to frequent brazilian waters. Full description and figures are given of speoies not hitherto known from this coast. Of the mentioned 2O speoies of hydroids, 5 are new for brazilian waters (Eudendrium carneun, E.capillare. Campanularia laevis, Amphisbet ia pulchella, Aglaura hemistoma); 3 are known only from the ooast south of Cabo Frio (Eudendrium carneun, Campanular ia laevis, Ob*lis commit sura 1 it. O.griffini, Thaumant ias raridentata, Orthopyxia crenata = O. lennoxent it, Geminella tubtilit, Amphisbetia pulchella); 7 are found both to the north and south of Cabo Frio (Pennaria fragil is, Clytia cylindrica = C.attenuate, Hebella scandens, Dynamena crisiodes f. typica, Sertularia marginata f. typica, Schisotricha billardi, Aglaophenia rigide); 4 species have a wide distribution (Eudendrium capillare, Obelia bicuspidata = Gonothyrea bicuspidata, Macrorhynchia philippina, Aglaura hemistoma) and finally of one species the known area of distribution was extended further south than Cabo Frio: Hebel la scandens. Cabo Frio has been tentatively considered as a natural zoogeographical frontier. The name Pennaria is used instead of Halocordyle, beoause the first described species certainly belonging to this genus was Sertolara pennara of Cavolini, later redescribed by Goldfuss in 1820 as Pennaria disticha. Stechow's opinion that considers oorreot the name Halocordyle is abandoned and the author now follows Bedot's view according to which the correct name for this genus is Pennaria. The speoies described for the Brazilian coast must therefore be called Pennaria fragilis (Van.). Eudendrium carneum was kept alive in sea-water aquaria. The by dran the have a well developed pseudohydrotheoa, they feed voraciously on small animals, mainly copepods and require thoroughly oxygenated water. They are rather difficult to raise in aquaria, and frequently the heads fall off or are resorbed. In these instances, the gonophores development proceeds at the expenses of the remainder portions of the coenosaro. The gonophores are produced around hydrants which become totally resorbed during their development, quiokly so in the male colonies, muoh more slowly in the female ones. Only one planula is produced in each female gonophore. The larvae emerge by rotating slowly using the orifice as fulcrum and so unscrewing themselves, so to speak, out of the gonangia. The pianolas locomotion is partly due to their oiliary covering and to a greater extent to gliding and active contraction and distension of their body. They are bright orange red and have a strong positive phototaxis. They become attached and from 60 to 66 hours after eclosion (water temperature from 23 to 84º C), the first polyp is completely formed. Eudendrium capillare was found in an aquarium and is here recorded for the first time for this coast. Campanularia laevis previously known only from cold sub antartic waters, was now found in the region of Cabo Frio at 67m depth. The hypothesis has been presented earlier of the existence of upwelling in this region (Vannucci 1951). A short description and figures are given of this species, which seems to be a cold water species. The gonothecae of Obelia bicuspidsta of these waters are here recorded for the first time. An extensive sinonimy of this species is presented, based principally on the work of Hummelinck. The finding of Orthopyxis billardi nom. nov., described by Billard as Eucopella crenata has made it possible to determine the sinonimy of Orthopyxis crenata and O.lennoxensis and clear the confusion until now existing for what concerns this species. Orthopyxis billard i has an interesting type of articulation by means of soft peridermic portions connecting successive hard segments of the peduncle. This articulation must confer to the peduncle a high flexibility associated with high resistance. Amphisbetia pulchella new for Brazil, was collected at Rio de Janeiro, a large, dead colony. Aglaura hemistoma, as was to be expected since it is a circumtrepical planctonic Trachynemid, was found to be abundant at 5-10m depth about 20º lat. S - 36º long. W, Jaseur Bank. Four species of Scyphoxoa are recorded, none of them is new. The first was described primarily by Fritz Muller from Sta.Catarina; it is the common Chiropsalmus quadrumanus, a voracious carnivore it is a very common species and is usually entangled in the fishermens nets, specially during summer. Chrysaora hysoscella was already known from Brazil, and was now collected in the low salinity waters of the region of Cananéia (southern part of the coast of the State of S.Paulo). Stomolophus meleagris and Lychnorhisa lucerna are two very common, even if not very abundant, species.
