. -IO SO IOO SEA MILES FROM LAND Fig. 76. Estimated total diatoms, and diatom group totals, survey I, Orange river line, 12-14 March 1950. The Biddulphiineae were almost entirely confined to the inshore stations on both series, though Eucampia zoodiacns was recorded in very small numbers from station WS 986, at the seaward end of the Sylvia Hill line. This same species accounted for most of the inshore totals for the group, as we had found farther north at this season, but here there was a small proportion of Cerataulina pelagica in addition. Soleniineae formed only a small proportion of these
. -IO SO IOO SEA MILES FROM LAND Fig. 76. Estimated total diatoms, and diatom group totals, survey I, Orange river line, 12-14 March 1950. The Biddulphiineae were almost entirely confined to the inshore stations on both series, though Eucampia zoodiacns was recorded in very small numbers from station WS 986, at the seaward end of the Sylvia Hill line. This same species accounted for most of the inshore totals for the group, as we had found farther north at this season, but here there was a small proportion of Cerataulina pelagica in addition. Soleniineae formed only a small proportion of these samples. The higher numbers at three inshore stations were due to the mainly neritic species Dactyliosolen mediterraneus and Leptocylindrus danicus. The very small totals for this group at offshore stations show that it was of some slight relative importance there, but only because of the prevailing poverty of the offshore phytoplankton. The offshore species included Bacteriastrum hyalinum, the more cosmopolitan Rhizosolenia spp. and R. simplex. The 'Pennatae' were more heavily outnumbered by the dominant chaetocerids at the inshore stations of these two lines than they had been farther north, but still ranked second among the diatom groups. The dominant inshore species—Fragilaria karsteni, Asterionella japonica and Nitzschia seriata —were the same as those recorded on the two previous lines. Offshore small numbers of Nitzschia dehcatissima, N. seriata and Thalassiothrix longissima accounted for most of the group totals, together with Fragilaria granulata at station WS 994. This species was recorded only at this one station during the first survey, but much more frequently and abundantly during the second, when it showed a con- sistently offshore distribution. The very small totals of' Pennatae' recorded at stations WS 986 and 994 just suffice to indicate greater relative importance than that of the chaetocerids, so clearly dominant at all the other stations of the Sylvia
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