358 DISCOVERY REPORTS 



which the Sixth Furcilia if not dominant had, as the length frequencies (Fig. 109) in both instances 

 show, clearly been in a position of dominance some very little time before. In this locality, and so late 

 in the year, it is difficult or impossible to attribute the existence of swarms of such backward develop- 

 mental stature to the January-April risings that take place in Weddell West itself, for the product of 

 such risings would long since have passed on to the east, to the South Georgia whaling grounds and 

 beyond. They must, in fact, have made their original ascent much farther upstream, and having 

 regard to the probable duration of the East Wind surface Ufe-cycle, and the probable rate of transport 

 in the west-going stream, the slope waters of the Princess Martha Coast are indicated as their most 

 likely locus of origin. The young, dominantly Sixth Furcilia, swarm encountered in November in the 



Fig. 109. Length frequencies of young first-year swarms in Weddell West in November. 



Bransfield Strait (p. 339, Fig. 95, Station WS 488) might also it seems have had a similar history, 

 while the underdeveloped mixed larval and adolescent swarms recorded in the East Wind drift between 

 0° and 30° E in January (p. 355, Fig. 107, Stations 2547, 2560, 2561 and 2562) could well it seems have 

 stemmed from the March risings that take place in the coastal waters of the Australian sector, such as 

 that, for instance, recorded (p. 311, Fig. 75) at Station 1713 in 120° E. The distance coastwise from 

 Station 1 7 1 3 to the mean position where these young January swarms were encountered is approximately 

 2500 miles, a distance which at a resultant rate of westerly drift of 8 miles a day the larvae would cover in 

 approximately 10 months' time, long enough it would seem for them to have grown to a state in which, 

 although the early adolescents were dominant, the Sixth Furcilia was still substantially repres ented. 



The principal facts relating to the growth and dispersal of the larvae in the surface stream may be 

 summarised then as follows: 



(i) In the Weddell drift the development from the First Calyptopis to the Fifth Furcilia stage 

 would appear at its fastest to be accomplished in from 60 to 70 days and the whole surface life-cycle, 

 Calyptopis i to Furcilia 6, in from 3 to 4 months. 



(2) In the East Wind zone the development is much slower, the surface life-cycle it seems taking 

 upwards of 9 months or more to complete. 



(3) The resultant rate of larval transport in the surface drift, both in the Weddell and East Wind 

 zones, is probably of the order of from 8 to 14 miles a day. 



i 



The larvae, adolescents and adults from the 



oblique and horizontal samples 

 The massed surface larvae 



Summer. The distribution and relative abundance of the massed surface larvae in summer (January- 

 March), based on the data from the towed stramin (0-5 m. and loo-o m.) nets, is shown in 

 Fig. no. As Eraser (1936, p. 138) remarks, the stramin net is selective in its fishing, giving a better 



