2 o6 DISCOVERY REPORTS 



these same meridians but from different years are plotted in Fig. 4. There are results for September 

 1936 in o°, June 1936 in 20 E and October 1932 in 8o° W. 



The results in September 1 936 compared with those in September 1 938 (Fig. 1 ) show the distribution 

 of the plankton to be essentially the same. In 1936 the shallower hauls gave higher volumes than in 

 1938, especially at sub- Antarctic stations. Antarctic St. 18 13 showed a particularly large volume at 

 50-0 m., but over 50 per cent of this was due to thirteen amphipods, and if they were omitted the 

 volume would be similar to that at St. 18 12, and both would be similar to the 1938 Sts. 2428 and 2430. 

 In both years the deeper hauls at Antarctic stations gave large volumes, while those in sub-Antarctic 

 waters were larger in 1938. 



0° SEPTEMBER 1936 



DEGREES SOUTH 

 36 38 40 42 44 46° 46° SO° 5 2° 



I I I I I I I I I 1 I I I I I I I 

 CTN I8O6 1907 1BOS IB09 IBIO 1BI2 1813 



J — 1 I 1 1 i »r 1 1 



1 



20 E JUNE 1936 



CTN IBOI 



1799 1796 



DEGREES SOUTH 

 56° 56° t 



I 1 1 I I 



imitT 



OM r 

 IOO 

 250 



SOO 



7SO 



80W OCTOBER 1932 



o DEGREES SOUTH 



56 58° 60° 6 2° 64 66* 



I I I I I 



CTN 9B4 986 987 989 991 993 

 J — I I I I AC | | 



I 



Fig. 4. Vertical distribution of the standing crop of zooplankton during September 1936 in o°; 

 June 1936 in 20 E; and October 1932 in 80° W. 



In 20 E there are no June observations in 1938, but the 1936 series shows the presence of deep 

 concentrations of plankton at a level intermediate between that in April and July 1938 (Fig. 2); and 

 similarly the surface volumes were on the whole not as large as those in April but greater than those in 

 July. The results for 1936 thus appear to fit reasonably well into the general picture presented by the 

 1938-39 series. 



The October results for 1932 and 1934 (fig. 3) in 8o° W, compare very well and show the same 

 essential features, particularly at stations in approximately the same latitude (i.e. Sts. 984 and 1441, 

 991 and 1447), although the 1934 sub-Antarctic hauls were greater than those in 1932. In both years 

 the plankton was concentrated deeper, the farther south the station. 



From these three diagrams it would seem that differences from year to year are not, in these instances 



