326 DISCOVERY REPORTS 



March-April. The distribution of the early FurciUas in March and April is shown in Fig. 86. 

 It seems clear from this chart that many of the Calyptopis swarms in Weddell West, probably all in 

 fact of those first encountered there in January, have now outgrown themselves, and, having reached 

 the early Furcilia stage, have begun to spread eastwards in the surface drift reaching in March a point 

 about a third of the way along Weddell Middle. Throughout April the eastward movement continues 

 until, towards the end of the month (Fig. 82), it would appear that the whole Weddell drift from 

 west to east, but most notably Weddell West and Weddell Middle, is carrying these stages in great 

 or very great abundance. There is again, however, evidence (Fig. 86) of a seemingly abrupt 

 termination of the larval drift somewhere in the neighbourhood of meridian 30° E. 



Fig. 87. Developmental condition of the larvae in the West Wind drift in localities affected by 

 surface emanation from the East Wind zone. 



It is not of course to be supposed that the gradual populating of the Weddell stream from end to 

 end with these stages is wholly brought about by the eastward movement of larvae sprung from risings 

 in Weddell West. Clearly if this were so the great distance to be covered would involve them in a 

 development beyond the early Furcilia state long before they could reach Weddell East. In so far 

 at least as the far eastern reaches of the current are concerned it is more likely that the early Furcilias 

 encountered there, spring, like the Calyptopes before them (p. 313), from risings in Weddell Middle, 

 such as that, for instance, recorded in March (Fig. 76, Station 1144) in 18° W. The local growth 

 of the dense concentrations of Calyptopes which in March and April (Fig. 75) are scattered 

 throughout the Weddell stream must also be involved in the gradual west to east populating of this 

 great current with the young Furcilia forms. Elsewhere the East Wind drift continues to be barren, 

 or virtually barren, of these stages and there have evidently as yet been no large-scale influxes on the 

 South Georgia whaling grounds, thoroughly sampled though they have been. Some minor concentra- 

 tions, however, both in March and April, have evidently drifted (p. 315) into the Bransfield Strait. 



The March-April chart for the early Furcilias provides two instances of how certain isolated and 

 probably strictly circumscribed areas of the otherwise barren West Wind zone may occasionally become 

 populated with substantial or moderately substantial larval communities through the influence of cold 

 tongues of surface water emanating from the East Wind drift. The more conspicuous of these is 

 provided by the April plot south-east of Kerguelen, the other by the April plot in the southern part 

 of the Drake Passage, the northward deflection of the East Wind water responsible for these occur- 

 rences being influenced in the first instance by the Kerguelen-Gaussberg submarine ridge and in the 

 second by the ridge Deacon (p. 315) supposes must exist to the westward of Charcot Island and upon 

 which Peter I Island probably stands. It is to be noted, however, that these Furcilias were from the 

 same two stations and samples as the Calyptopes referred to on p. 315. The developmental condition 

 of the larvae in these localities (Stations 383 and 861) is shown in Fig. 87 and it is somewhat 



