HORIZONTAL DISTRIBUTION OF LARVAE 321 



except at one station (St. 452) E. triacantha has not exceeded 100 per 20 min. haul, whereas E. superba, 

 even when only those over 20 mm. are considered, exceeded 10,000 at four stations. It also shows 

 that, although mixing of these species does occur, in general they are confined to different water 

 masses, E. triacantha to the West-Wind drift and E. superba to the East Wind and Weddell drifts. 

 The mixing is only found at the junction of these water masses and is most marked in the region of 

 South Georgia where, as pointed out by Hardy and Gunther (1935), hydrological conditions are 

 complex. 



HORIZONTAL DISTRIBUTION OF LARVAE 



The larvae considered here include the first, second and third calyptopis stages and the seven furcilia 

 stages described by John (1936, p. 278). The data presented in Fig. 7 are based upon night hauls 



600 



500 400 



NORTH 



400 500 



SOUTH 



NAUTICAL MILES 

 Fig. 7. The number of larval E. triacantha in a series of shallow oblique night hauls with the i m. net from north-south lines 

 of stations plotted according to the distance in nautical miles from the Antarctic convergence. The number per haul is ex- 

 pressed as a percentage of the total catch for each line. The position of the convergence has been taken from Mackintosh 

 (1946, Table 9). 



between 100 m. and the surface with N looB and it is possible that the mesh of this net is not small 

 enough to take representative samples of the first and second calyptopis stages. However, the 

 meridional lines of stations used in preparing this figure were worked in December, January and 

 February, during which months the predominant larval stages, as will be shown later (p. 334), are the 

 second to seventh furcilias. The data for the larvae have been treated in the same manner as those for 

 the adolescents and adults, that is, the number of larvae taken at each station is shown as a percentage 

 of the total number of larvae taken along each line. 



The total north to south range of the larvae, as shown in this figure, is approximately the same as 



