no DISCOVERY REPORTS 



These same conditions are continued with small modifications towards the north near 



South Georgia and the Shag Rocks. 



The second reason is probably to be found in the bathymetric conditions. West of 

 Graham Land and in the neighbourhood of the South Shetlands, South Orkneys, South 

 Sandwich, South Georgia and the Shag Rocks there are extensive areas of comparatively 

 shallow water, and on the Scotia Arc joining these regions {vide Herdman, 1932, p. 214) 

 the sounding is generally less than 2000 m. If, as will be suggested later, the eggs de- 

 velop near or at the bottom in comparatively deep water, the depths in these regions are 

 probably most suitable. 



Fig. 31. Distribution of eggs of Euphausia superba. 



The reason for the particular abundance in the Bransfield Strait area may be that tem- 

 perature and salinity or the bathymetric conditions are particularly suitable. For, in the 

 Bransfield Strait and separated from the surrounding seas by submarine ridges rising to 

 within 250-600 m. of the surface, there are extensive basins with soundings from 500 to 

 2000 m. These basins may be particularly favourable for the production and develop- 

 ment of eggs. One other striking feature of this region which may make it suitable is the 

 homogeneous condition of the water column. Over the shallow ridges the water is 

 almost completely mixed, and even in the deep basins there are only small changes of 

 temperature and salinity with depth. 



The eggs were found in nets fished through water of which the temperature varied 

 from — I -So to 2-02° C, but the greater number of catches was in water of temperature 



