A theory is given to account for the CROMWELL Current-the Equatorial Undercurrent. The equatorial upwelling is closely related to the Current, and a remarkable similarity between the equatorial circulation and the circulation in the coastal upwelling regions. The widths of the equatorial upwelling as well as of the CROMWELL Current the maximum speeds of the upwelling and of the CROMWELL Current, the depth of the core and the thickness of the CROMWELL Current, are all found to be explained quantitatively. The rate of change in the CORIOLIS parameter with latitude and the mean vertical stability of the waters are essential to determine those length scales of the phenomena. The easterly wind stress over the equatorial region is responsible for the processes.

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The results of experiments on diffusion of dye with a scale of less than 1 km in Santa Monica Bay, California are compared with two theories, one initiated by G. I. TAYLOR based on statistical theory of turbulance and the other recently proposed by JOSEPH and SENDNER based on the probable velocity of diffusion. The change of a radius of a dye patch with time, after released from an instantaneous point source, is well explained by the former theory with the assumption of small diffusion time. Two sets of experiments yield the average turbulent velocity of 1 cm/sec or less which is about one tenth of the mean cnrrent. Experiments on the diffusion from a continuous point source also confirm the validity of the TAYLOR theory under the condition of a small distance, giving the same order of the turbulent velocity.

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STOMMEL's method of determining depth of no meridional motion is modified so as to be applied to hydrographic data which do not reach the bottom, by adopting two types of extrapolation formula for the mass transport below the reference level of dynamic calculation.

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A method is described for rapid determination of surface tension of the sea water in situ. By this means the lowering of surface tension is found in the region of “Slicks”, where the water frequently contains nlenty of organic matter.

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In order to study the distribution of total iron and manganese in Urado Bay the authors made determinations of these elements.
The quantity of total iron in sea water ranges from 0.2 to 15.9 microgram atoms per liter, and that of manganese from 0.2 to 6.2 microgram atoms per liter.
It was discovered that these two elements are contained in larger quantities in bottom water which has been affected by the bottom mud, and that their distribution in bottom water varies with the topographical features of the sea floor.
These findings lead the authors to presume that iron and manganese are highly con-centrated near the “shiome, ” or current rips.

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The present paper dealt with the seasonal variation of Sagitta crassa on the basis of the appearance of the collarette, and dealt with the effect of the water temperature and the chlorinity of the sea water that have the important effect upon such variation. The materials for this study were collected from November ('54) to March ('58) at one station (St. 22), from December ('54) to February ('55) at 20 stations and from November ('55) to October ('56) at 6 stations in the neighbouring sea of Mukaishima (Inland Sea of Japan).
In the case of the study, the collarette of S. crassa is distinguished four classes as shown in Fig. 2 according to the degree of the distribution. Accordingly, the collarette of type form of S. crassa is A class and the collarette of f. naikaiensis is D class.
S. crassa occurred neighbouring sea of Mukaishima has three main spawing seasons (February-March, May-July and November-December) in which the generation alternates. In two generations that the individuals mainly spawn from May to July and from November to December, the collarette of S. crassa is D class or C class of low degree. But in the generation that the individuals mainly spawn from February to March. the collarette is ableto develop into C, B and A class in order. In that case, the collarette of S. crassa comes into C class from December to January, into B class from January to February and into A class on and after February.
The water temperature has the important effect upon the development of the collarette mentioned above. The occurring of the individuals that the collarette developed into A and B class is limited in the case of the water temperature dropped under 11.5°C, and the rate of the occurring is raised when the water temperature has dropped under 9.5°C. In other hand, the individuals that the collarette has developed into C class rarely occur even if the water temperature has rised upper 20°C, but the rate of the occurring is raised when the water temperature has dropped under 11.5°C and into C class within 17.4-18.6‰.
The chlorinity of sea water has the important effect upon the development of the collarette of S. crassa, too. The collarette develops into A class when the chlorinity of sea water is within 17.5-17.8 ‰, into B class within 17.4-18.1‰ and into C class within 17.4 18.6 ‰.
Thus, the collarette of S. crassa develops when the water temperature and the chlorinity are confined within fixed limits.

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