330 DISCOVERY REPORTS 



a particularly large one and dominance or otherwise could only be established if the relative abundance 

 of the Calyptopis stages, then unknown to Hansen, had itself been established at the same time. In 

 fact all that can be concluded from this isolated yet highly important observation is that in this 

 particular locality, and perhaps elsewhere in the East Wind drift as well, the early Furcilias do begin 

 to appear in some, perhaps small, measure of abundance round about the beginning of May. 



Since the first substantial gatherings of early Furcilias were recorded at Stations 361 and 362 (p. 314, 

 Fig. 77) on 25 February and the earliest substantial rising of First Calyptopes was recorded at 

 'Norvegia' Station 42, 11° farther west, on 18 January, there would appear to be some grounds for 

 supposing that in the Weddell drift the growth from the First Calyptopis to the First Furcilia stage 

 takes upwards of 40 days. 



The principal facts relating to the distribution of the early Furcilia stages, a composite view of which 

 is given in Fig. 89, are then as follows: 



(i) They first appear in small numbers in Weddell West and on the South Georgia whaling grounds 

 in January, but it is not until late February that in the former locality substantial numbers have 

 been recorded. 



(2) Now crowding the near surface stratum, they gradually spread eastwards in the surface stream, 

 covering the whole of the Weddell drift from west to east by the end of April. 



(3) The gradual populating of the Weddell stream with these stages is brought about partly through 

 the eastward movement of larval risings that take place in Weddell West, partly through the eastward 

 movement of similar risings that take place in Weddell Middle and partly through the local growth 

 of the Calyptopis population. 



(4) The May-June distributional chart again emphasises the role of the Weddell drift as the 

 principal carrier of the larvae and instrument of their dispersal in the Atlantic sector. Its influence 

 is again seen to cease rather suddenly in the neighbourhood of 30° E. 



(5) In May and June the whole of this surface stream is probably carrying larvae predominantly 

 in the early Furcilia stage. 



(6) While there is some drifting of Furcilias 1-3 into the Bransfield Strait in March and April it is 

 probably not until May that they begin to reach the South Georgia whaling grounds in any sub- 

 stantial measure of abundance. 



(7) In the late-spawning, slow-growing region of the East Wind drift there are virtually no early 

 Furcilias to be found from January right through to April and, judging from the backward condition 

 of the swarms encountered there in late April, it seems likely that even throughout May and June 

 they are still far from abundant. 



(8) There is some evidence that in the Weddell drift the growth from the First Calyptopis to the 

 First Furcilia stage takes upwards of 40 days. In the East Wind zone this development, it seems, must 

 be spread over a much longer period. 



(9) In its major aspects the distribution of the early Furcilias, like that of the Calyptopes, is 

 essentially a feature of the East Wind- Weddell surface stream, the West Wind drift being barren, 

 or virtually barren, except again where it is affected by tongues of cold water emanating from the 

 East Wind zone. Such larvae as do get carried north in these tongues evidently encounter better 

 feeding than they do in higher latitudes and, developing more rapidly than their contemporaries in 

 the East Wind drift, quickly outgrow them. 



(10) Finally, it will be noted how both slow growth and ice conditions in the East Wind zone 

 combine to render the existence of the early Furcilias in the higher latitudes of Antarctica virtually 

 impossible to disclose, leaving us with the impression that up to the end of June these stages are 

 confined almost exclusively to the lower latitudes affected by the Weddell stream. 



