Samples used in this study were collected from 93 stations during the following four survey periods; (1) August 8-11, 1971, stations 1-45 from the inner bay; (2) November 20, 1973, stations 46-50 from the northeastern inlet (Inohana-ko); (3) September 14-17, 1975, stations 62-93 along the bay coast and ponds; (4) September 15, 1975, stations 51-61 from the open sea (Enshu-nada). These stations were designed to cover effectively the whole area at intervals of approximately 1.5 km.

The samples from stations of surveys 1 and 2 in the bay area were collected by means of the Phleger-type core sampler (Phleger, 1951, 1960) and a modified Ockelmanntype bottom net sampler. Surveys were made by the research boat Kamome-maru of the Hamana-ko Branch, Shizuoka Fisheries Experimental Station. The result of studies on sediments and foraminifers of these samples has been given in previous papers (Ikeya and Handa, 1972; Ikeya, 1977). The collections of samples during surveys 3 and 4 were made by a Ockelmann-type bottom net sampler operating from a charter boat in survey 4 and from land in survey 3.

Sampling data (water depth and bottom character) are listed in table 1, and the locations of the sampling stations are shown in text-figure 1. Twelve among the 93 stations coincide with fixed stations where regular meteorological observations have been made monthly by the Hamana-ko Branch, Shizuoka Fisheries Experimental Station, since 1949.

Quantitative samples of surface sediments were taken using a Phleger-type core sampler with a plastic inner tube. The samples used for quantitative analysis of ostracod fauna are composed of a few centimeters of the bottom water with suspended sediment in the tube and the uppermost 1 cm of undisturbed core of sediment, which is 3.5 cm in diameter. The standing crop size of ostracods is very small in comparison with that of foraminifers. Thus, the volume of sediments obtained with a core sampler designed for foraminiferal research is usually too small to analyze species diversity of ostracods. Supplementary sampling was made by an Ockelmann-type bottom net sampler at the localities where the core sampling was made. At stations with coarse sediments, only the Ockelmann-type bottom net sampler was used for sampling. The remodeled Ockelmann-type bottom net sampler is 15 cm wide and is designed to be drawn for about 3 m on the bottom to collect the upper-most one centimeter or less of surface sediments, including suspension at the water-sediment interface. A few liters of sediment are thus obtained.

These samples were placed in a plastic bottle and fixed immediately with 5% neutralized formalin solution. In the laboratory all samples were washed with water through a 200-mesh sieve (opening of 0.074 mm). Half of the washed sediment is preserved in 70% alcohol to keep ostracods for dissection. In order to facilitate discrimination of living ostracods and dead carapaces, the remaining half of the sediment was stained with rose Bengal. After staining, the samples were washed over again through a 200-mesh sieve and then dried. The bottom net samples with abundant ostracods were divided into several parts to obtain a workable size sample with about 200 valves of ostracods. In the other samples, all specimens of ostracods were picked up regardless of the volume of sediment. The volume of sediment used in this analysis is given in tables 3 through 5. After identification of species, the number of individuals in each taxon was counted, distinguishing between "living" and "dead" specimens for every station. The result are also presented in tables 2 through 5. The living individuals of ostracods were discriminated easily as the well-stained reddish carapaces with comparatively stout appendages. All ostracod specimens used in this study are deposited in the Institute of Geosciences, Faculty of Science, Shizuoka University.