174 DISCOVERY REPORTS 



Genus Podolampas, Stein 

 Podolampas bipes, Stein. 



Lebour, 1925, p. 160, fig. 52 b. 



At three tropical stations. 



Sub-Class SILICOFLAGELLATA 



These were not identified specifically, but were of tolerably constant occurrence in 

 the more oceanic areas within the Antarctic Zone, frequently in moderately large 

 numbers. Most of them appeared to be referable to the well-known forms Dictyocha 

 fibula, Ehrb., and Distephanus speculum (Ehrb.), Haeckel. 



SCHIZOPHYCEAE, etc. 

 Pelagothrix spp. 



Observed in very small numbers at one tropical and at one sub-tropical station. 



Trichodesmium thiebautii, Gomont. 

 Wille, 1903, p. 17, fig. 13. 



Observed sparsely at four stations towards the northern end of the line worked in 

 long. 30° W. Vast swarms discolouring the surface of the sea were encountered in about 

 40° S between Montevideo and South Georgia (see p. 26). 



Richelia intracellularis, Schmidt. 

 Wille, 1903, p. 26, fig. 23. 



Endophytic in Rhizosolenia styliformis at one tropical station. 

 Coccosphaeriales. 



These are known to be important producers in the warm and temperate seas in the 

 South Atlantic. The method of collection employed was that most suitable for obtaining 

 a working knowledge of the almost entirely diatomaceous phytoplankton of Antarctic 

 surface waters — viz. vertical net hauls. Unfortunately nets do not capture these 

 organisms, and as our work in warmer waters was not extensive, other methods were not 

 employed. At one tropical station small numbers of Coccolithophora leptopora, Murr. 

 and Blackm., were observed. 



Phaeocystis brucei, Mangin. 

 Mangin, 1922, p. 82, figs. 25-7. 

 This species is known to occur in our southern area, and was abundant in the pack- 

 ice to the east of South Georgia in October 1930 (early spring), where it formed the food 

 of post-larval Euphausio superba. Not observed at any of the phytoplankton stations. 

 Undoubtedly very sporadic in its occurrence. 



Halosphaera viridis, Schmitz. 



Lemmermann, 1903, p. 38, fig. 128. 

 Also known to occur in our southern area, but not observed in this material. Possibly 

 confounded with the numerous microspores of Chaetoceros criophihim and Corethron 

 valdiviae at some stations round South Georgia in spring. 



