. Fig. 32. Distribution of Metanauplius of Euphansta superba. and 1000 m. In areas of open water away from the influence of the ridge of the Scotia Arc, and, in the case of St. 648, away from the influence of the Antarctic convergence, the larvae are entirely restricted to depths below 500 m. It is at such depths that the bulk of MetanaupUi are found, and it is important to consider the conditions of their environment. They are found in the warm deep water and not in cold Antarctic surface water. The properties of this warm deep-water layer are described by Deacon (1933, pp. 222 et seq.), and
. Fig. 32. Distribution of Metanauplius of Euphansta superba. and 1000 m. In areas of open water away from the influence of the ridge of the Scotia Arc, and, in the case of St. 648, away from the influence of the Antarctic convergence, the larvae are entirely restricted to depths below 500 m. It is at such depths that the bulk of MetanaupUi are found, and it is important to consider the conditions of their environment. They are found in the warm deep water and not in cold Antarctic surface water. The properties of this warm deep-water layer are described by Deacon (1933, pp. 222 et seq.), and it is not necessary to recapitulate them here beyond pointing out that he states that the depth of the maximum temperature in 57° 30' S is 600 m. and of maximum salinity 700 m., and that the usual component of movement is from warm to cold regions and not from cold to warm. Now if the temperature range within which Metanauplii were taken is examined, it will be seen that although the larvae are occasionally found in water of temperature below 0° C. they apparently favour the warmer water. Thus at St. 647 the range is be- 15-2
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