248 DISCOVERY REPORTS 



the succession so far as this region is concerned, its autumn distribution being rather similar to that 

 shown by Stephanopyxis turris, but without the apparent inhibition in the richest part of the Chaeto- 

 ceros zone. 



Aster ionella japonica was the most abundant of the 'Pennatae' in the rich coastal waters, sometimes 

 extending seawards, but in comparatively small numbers, as can be seen from Figs. 88 and 89. It was 

 quite uninhibited by the huge quantities of chaetocerids, among which it flourished during the autumn 



20° 



25°. 



S 

 O 

 U 



T 

 H 



302- 



SURVEY : I 



•am MO WE POINT 



■olio 5 □ 



io 5 -io 6 



> 10 



WALVIS BAY 



SYLVIA HILL 



ORANGE 

 R. 



IO 15 EAST 



Fig. 87. Distribution of Eucampia zoodiacus, survey I, 

 March 1950. (Station numbers are shown in Fig. 1.) 



20- 



25°H 



S 

 O 



u 



T 

 H 



30°- 



NIL Q 



MOWE POINT 



VALVJS BAY 



SURVEY- I 



SYLVIA HILL 



ORANGE 

 R. 



10° 15° EAST 



Fig. 88. Distribution of Asterionella japonica, survey I, 

 March 1950. (Station numbers are shown in Fig. 1.) 



survey. Less numerous, but almost equally widespread in spring. The narrowing of the coastal 

 zone and apparently increased tendency towards fanning-out of the coastal waters in the extreme 

 north of the area at that season were features shown in some degree by other important inshore 

 species. 



The distribution of both the species of Fragilaria met with is shown in Figs. 90 and 91. Fragilaria 

 karsteni proved to be the most strictly coastal of the diatoms encountered in the plankton here during 

 both surveys ; one might almost describe it as neritic. Though somewhat less widespread in autumn 

 than it was during the spring survey, the heaviest individual hauls of the species were obtained in 

 autumn near Walvis Bay. 



Fragilaria granulata was a species of the outer shelf stations and offshore waters found mainly in 



