. CORETHRON VALDIVIAE core:thron valdiviae spineless chains RHIZ050LENIA CURVA organisms from remaining in the optimum light zone long enough for extensive pro liferation. The presence oiRhizosolenia alata f. gracillima at this particular station is interesting, as this form has been encountered in abundance only in the northern part of the BeUingshausen Sea at midsummer, and just outside the South Shetlands later in the year, and in Bransfield Strait. In this last locality it evidently comes in with the old Bellingshausen Sea water from the western end, and its appearance here to the east qui
. CORETHRON VALDIVIAE core:thron valdiviae spineless chains RHIZ050LENIA CURVA organisms from remaining in the optimum light zone long enough for extensive pro liferation. The presence oiRhizosolenia alata f. gracillima at this particular station is interesting, as this form has been encountered in abundance only in the northern part of the BeUingshausen Sea at midsummer, and just outside the South Shetlands later in the year, and in Bransfield Strait. In this last locality it evidently comes in with the old Bellingshausen Sea water from the western end, and its appearance here to the east quite early in the season may be due to multiplication of the remnant of the autumn invaders of the previous season. On the line just described, the great increase in phytoplankton with decreasing temperature to the south of the Antarctic convergence was very well illustrated, but on a series of observations taken between the Falkland Islands and South Georgia at the end of February 1930 (WS 518-36), the normal state of affairs was reversed, there being a fairly rich phytoplankton in the sub-Antarctic surface water, while that to the south-east was comparatively poor. On this line also the convergence was much less sharply defined than usual, the probable reasons for this being mixing caused by the newly discovered bend or curve in the con- vergence immediately to the west of the centre of this line, and as already noted, the abnormal warmth of the old Antarctic surface water in the vicinity of South Georgia towards the end of this season. It will be seen from Table XVIII, in which the full analyses of the hauls on this line are given, that pro- ceeding east by south from the Falkland Islands, fairly heavy catches were obtained at the first three stations in definitely sub-7\ntarctic water. This is perhaps rendered even clearer by Fig. 34, where the proportions of some of the leading forms are also shown as percentages of the catch at each station. It will be seen that few species
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