The return voyage from the Island of Trindade (Besnard, W., 1951, p. 37-48) to Rio de Janeiro was made on board of a trawling boat, "Vega", and the established route was through the series of banks that occur between the continent and the group of islands Trindade and Martim Vaz. The banks are accurately placed on the map and the deepness of the ocean above them, correctly stated. Dredgings, due to lack of time and inappropriate gear available on board, brought back only samples comparable to those of the insular platform of the island of Trindade, more similar to the collections made nearer the island, and gradually differing from them on the banks located closer to the continent. As is shown in the accompanying schematieal section, the submarine profile is extremely irregular, there being instances of falls of over 2.000 meters in the distance of a few meters. It seems, therefore, reasonable to imagine that there is, between the continent and the island a series of mountains and ridges possibly of eruptive nature. However, the schema is necessarily very incomplete due to the scarcity of the soundings. The voyage was altogether much too short for more than a quick glance, that produced enough material to show that it is an interesting region from several points of view and worth of a more detailed study.

The oceanographic work realized during 10 days in the surroundings of the eruptive island of Trindade, 20º30'36" lat. S - 29º19'26" long. W, had as principal aim the determination of the insular plateau, whose knowledge was very insufficient. Thus were established some oceanographic stations and sounding lines were realized by means of an echobathymeter whose responses were initially verified with mechanical soundings obtaneid by means of a Thomson sounder. The insular plateau is very narrow and exhibits a sudden fall between the 100 and 120 m. depth line at 740 m. - 2950 m. from the coast. Its greatest depth is of 108,30 m. and its mean inclination is of 8,12%. The plateau of the island of Trindade is separated from that of the neighbouring group of Martim Yaz by great depths. The bottoms are rocky near the coast, the blocks having been produced by the rupture of the magmatic mass of the island. Further away from the coast, the size of the rocks gradually diminishes up to the fine sand thickness. In the litoral zone there are abundant tufts of living Lithothamnion with a rich associated flora and fauna, which partly covers the rocks themselves. Further off at sea, the spheres of the dead alga with its commensals are cimented together by sedimentation. The spheres are further broken up and become an integrating part of the sand. The results of the physical and chemical analyses of the sand bottoms are shown in tables 2 and 3. The coast is either of abrupt rocky walls falling down to sea level, or of shores, made of pebbles or of sand. Anyhow, there are frequently Lithothamnion terraces slightly inclinated towards the bottom (chemical analysis table 1).

O trabalho em questão teve como principal objetivo servir de nota introdutória à pesquisa que se processa no setor Iguape-Cananéia, situado no litoral sul do E. de S. Paulo. Pareceu ao autor providência inadiável efetuar tal investigação, em virtude do caráter muito especial do sistema lagunar, considerado, por assim dizer, como chave indispensável ao entendimento do que se passa no conjunto da região. Inicialmente, procurou o autor apresentar um ensaio hipotético da gênese da região. A primeira parte desse estudo figura no número 1 deste Boletim e compreende o exame da questão, partindo da pre-existência de um golfo pintalgado de ilhas montanhosas e do seu entupimento em consequência do carreteamento de produtos terrígenos decorrentes de erosões. Seguem-se a atuação dos ventos dominantes e das correntes de maré, o papel retentor desempenhado pela vegetação dos mangues e a esquematização do processo, em quatro fases diferentes e que justificam as modificações hipotéticas aventadas. Na segunda parte, trata o autor da descrição dos diversos aspectos da região lagunar, dividida em zonas naturais, como segue: la. Canal principal: 2.º Mar do Cubarão; 3.º Baía do Trapandé e suas dependências; 4.º "marigots"; 5.º canal do Ribeira de Iguapé e 6.º canal e Mar do Ararapira. Conquanto se trate de trabalho particularmente mais aprofundado na parte relativa à geografia física, nele se situam pesquisas oceanográficas, hidrológicas, botânicas, físicas, químicas e de zoologia geral, decorrentes da necessidade premente de se conhecer um grande centro produtor de fitoplancton representado, sobretudo, por Diatomáceas.

This short essay about the lagoon Region of Cananeia, the first part of which has appeared in the nº 1 of the same Bulletin, has the special finality of serving as an introduction to the different notes, studies and works concerning this region of extreme interest. Some of them have already been published in the nº 1 of this Bulletin. This introduction seems to be, if not indispensable at least useful, regarding the very special character of the lagoon system, a circumtance which makes it sometimes very difficult to understand certain details without knowing the totality of the Region and its pecularities. We thought it to be useful, to understand the finality and to facilitate the comprehension of certain phenomena, to draw an hypothesis of the genesis of the Region. The first part, already published in nº 1, comprises a summarian description of the Region as a whole and presents an hypothetic essay of its genesis: the pre-existence of a gulf rich in mountainous islands; its obstruction by the residues of erosion and by terrigenous materials; the work of the predominating winds and tide currents; the importance of the mangrove, etc. An abbreviated schematization of the process was presented in four hypothetical phases. The second part, the present one, is dedicated to the description of the different actual aspects of the lagoon Region: Division of the Region in natural zones: 1.º The Main Channel; 2.º The Mar do Cubatao; 3º The Bay of Trapande, and its dependencies; 4º The "marigots"; 5.º The canal of the Ribeira de Iguape and 6.º The Mar do Ararapira and its canal. A certain number of pecularities has chiefly drawn our attention to it; among others - the structure of the "marigots" of The second type; the part played by the oscillation of the tides in their maintainance and chiefly the problem of the phytoplancton in the lagoons and its distribuition in the different zones. These latter researches which represent up to now but an attempt for an orientation towards a plan of further studies, allow us already to suppose that the distribution of the phytoplancton in the "marigots" of all the southern part of the system, as well as in a great part of the body of the lagoon itself, is dependant on a determinate regime of salinity, represents zones of intensive production of phytoplancton, specially Diatoms. Finally another statement: the outflow of large masses of phytoplancton towards the ocean at every ebb.

Na região de São Sebastião e canal do mesmo nome foi capturado um lote de larvas e alevinos de Sardinella aurita Cuv. & Val.. Esse lote compunha-se de três séries, cada qual proveniente de uma coleta diferente e oriunda do mesmo engenho de captura. O lote compunha-se de espécimes providos de portes muito diferentes, variando de 22 mm., a 105 mm.. Após as medições (em milímetros) os diagramas de variabilidade revelaram a existência de numerosos ápices (cerca de 20) que se revelaram confusos e ilegíveis. Depois de se ter tentado várias operações, conseguiu-se separar cinco curvas mais ou menos razoáveis. A pesquisa levada a efeito nessas curvas de variabilidade, não teve outro objetivo sinão o de procurar uma explicação para o conjunto dos diagramas obtidos. A existência de várias curvas prova que nos encontramos em presença de uma série de posturas consecutivas.

Dans la région de São Sebastião, dans le canal du même nom a été capturé un lot de larves et alevins de Sardinella aurita: Cur. & Val.. Ce lot étant composé de trois séries, chacune étant le résultat d'une levée séparée du même engin de capture. Le lot était composé de spécimens de tailles très différentes allant de 22mm. à 105mm. Après mensurations (au millimètre) les diagrammes de variabilité ont montré l'existence de nombreux sommets (prés de 20) mais se sont avéré confus et illisibles. Après avoir tenté diverses opérations on est parvenu à séparer 5 courbes plus ou moins plausibles. La recherche de ces courbes de variabilité n'avait comme but que l'explication de l'ensemble des diagrammes obtenus. La découverte de plusieurs courbes prouve que l'on est en présence d'un série de pontes consécutives.