304 DISCOVERY REPORTS 



Coast, the occurrences are exclusively of the Metanauplius and the First Calyptopis stage. While this 

 may again simply be due to the fact that in most instances our nets did not go deep enough to sample 

 the Nauplii, fifteen negative observations down to 1500 m. along the 0° line, nine in March and six in 

 April, rather seem to indicate that in the Weddell zone at least the Second Nauplius is now^ perhaps 

 approaching the end of its natural span. 



The chief point of difference between this and the January- February distribution is that whereas 

 in January-February there was a marked crowding of the main concentrations of the deep larvae in 

 a circumscribed region of the western Weddell drift, in March-April this has given place to a system 

 of rather widely scattered concentrations which by April stretch all along under the drift from west to 

 east. The wide scatter of the more important occurrences might again it seems be taken to indicate 

 that some or all of the deep larvae are now, particularly in April, becoming scarcer in the plankton. 



The January-February chart (p. 301, Fig. 70) shows a pronounced concentration of the deep 

 larvae in Weddell West. By March this concentration has spread to about half-way along Weddell 

 Middle, a west to east shift that is more likely, I think, to be due (p. 100, Table 17) to the eastward 

 movement of the bottom water carrying the hatching eggs and developing Nauplii, rather than to an 

 oceanic spawning having occurred in Weddell Middle some time after the major larval outburst 

 farther west. In view of its great distance from the north Graham Land coast the major April 

 occurrence of deep larvae towards the eastern end of the current (Fig. 71, St. 2346 in 20° E) could 

 hardly, however, be ascribed to such a movement. On the contrary it seems it must be taken as repre- 

 senting an instance, uncommon although our net hauls suggest such instances to be, of oceanic spawning 

 far away from land where the females had either shed their eggs in the upper layers of the plankton, 

 the eggs subsequently sinking, or had sought great depths to spawn. In either event this spawning could 

 not have occurred at (or over) the place where the deep larvae were found, it being obvious that if it 

 had the interplay of the successive water movements in which the eggs and resultant larvae subsequently 

 became involved would have led to the displacement of the latter possibly far away from it. 



Apart from one exceptional occurrence with which I shall deal presently, there is no major evidence 

 of hatching anywhere outside the Weddell stream except again, as in January-February, in the slope, 

 coastal or near-coastal waters of the East Wind drift. Two Metanauplii it is true, were taken on the 

 South Georgia whaling grounds and one in the Bransfield Strait (all March records), but otherwise 

 both heavily sampled regions are barren. Such considerable part, too, of the Pacific sector as has been 

 examined is also barren. 



Of the four major East Wind occurrences there is one in March of exceptional interest. At Station 

 2603, it will be recalled (p. 93, Table 14), a very large number of Second Nauplii along with some 

 Metanauplii were discovered very close to the bottom in the slope water off the Princess Martha 

 Coast. The sounding here was 1450 m., the deep net being sent down to 1400 m., a depth which, 

 although supposedly only 50 m. from the bottom, might well in fact have been closer to it since, while 

 the vertical work was in progress, the ship for all we know might have drifted into shallower water. 

 No eggs were found at any of the seven levels examined at this station. The total deep larval population, 

 however, was disposed vertically as follows: 



