. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. SAGITTA GAZELLAE 267 It is also evident from Fig. 20 and from Table 18, Appendix, which gives the numbers plotted on Fig. 20, that there is a considerable decrease in numbers with depth. This confirms the evidence from the series of vertical stations mentioned above. The evidence from the vertical series suggests that the maximum concentration of S. gazellae is in the 100-50 m. layer, and this confirms Bollmann's (1934) statement for both S. lyra and S. gazellae (considered together). The data i
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. SAGITTA GAZELLAE 267 It is also evident from Fig. 20 and from Table 18, Appendix, which gives the numbers plotted on Fig. 20, that there is a considerable decrease in numbers with depth. This confirms the evidence from the series of vertical stations mentioned above. The evidence from the vertical series suggests that the maximum concentration of S. gazellae is in the 100-50 m. layer, and this confirms Bollmann's (1934) statement for both S. lyra and S. gazellae (considered together). The data in Fig. 20, however, suggest that the main concentration is between 100 and 150 m. The numbers in this figure have been plotted against the mean depth of each haul and the concentrations between no and 135 m. may well have been taken at a depth of less than 100 m., as the nets which took them fished into the 100-50 m. layer. The data from the vertical nets may be considered to be more reliable in this respect. The depth range of the species obtained from the samples available extends down to 3000 m., but it is quite possible that its total range may reach to the bottom; at great depths specimens are rare. Table 12 shows the numerical data from thirty-five daylight and thirty-five night vertical stations and suggests that there is no diurnal migration in the species; Fig. 21 shows the depth distribution during the 24-hour Station 461, and confirms the absence of diurnal migration. 2230 DARK HOURS 0230 0430 IO30. Fig. 21. The vertical distribution of 5. gazellae at Station 461 showing absence of diurnal migration. Data from oblique 1 m. nets. Horizontal scale 1 mm. = 2 individuals. Fig. 22, which has been constructed by the method described by Mackintosh (1934, p. 377), shows the monthly vertical distribution of the species in the meridian of o°, and demonstrates the seasonal vertical migration in winter. Table 19, p. 278, gives the numerical data from which the figures were comp
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