570 Annals of the South African Museum. 



Previously recorded by Wille from South Africa; by G. S. West 

 from Great Namaqualand. 



Genus GLOEOCAPSA Kuetzing. 



1. Gloeocapsa rupicola, Kuetzing, Spec. Alg., 1849, p. 221 ; Forti, 

 op. cit., p. 38. 



Sample 42 (not uncommon). 



Genus APHANOCAPSA Naegeli. 

 1. Aphanocapsa elachista, W. & G. 8. West, On some Freshw. Algae 

 from the W. Ind., Joum. Linn. Soc, Bot., xxx, 1894, p. 276, PI. XV, 



figs. 9, 10; Forti, op. cit., -p. 73. 



Var. conferta, W. & G. S. West, Period. Phytoplankton Brit. Lakes, 

 Journ. Linn. Soc, Bot., xl, 1912, p. 432, PI. XIX, fig. 1. 



Sample 39. 



Long, colon., 81-144 /x; lat., 68-105 /a: diam. cell., L5-25 /;.. 



Genus APHANOTHECE Naegeli. 



1. Aphanothece microspore/, (Menegh.), Rabenhorst, Fl. europ. Alg., 

 ii, 1865, p. 64; Forti, op. cit., p. 84. 



Sample 23. 



Diam. cell., 5"5— 6 ju, ; long, cell., 10-11 p. This Aphanothece seems 

 to accord best with the above species. The cell-contents were very 

 slightly, but invariably, granular, and the general mucilage w r as dis- 

 tinctly yellowish in places.* I can find no mention of these features 

 in any of the published descriptions. The sheaths of the individual 

 cells were mostly completely diffluent, but were visible at a few points. 

 This species certainly comes close to A. naegelii, Wartm. 



Genus MICROCYSTIS Kuetzing. 



1. Microcystis sp. 



Samples 14, 15 (abundant). 



This is possibly a form of M. aeruginosa, Kuetz. (Syn. : Clathro- 

 cystis aeruginosa (Kuetz.), Henfrey), which is known to be very 

 variable. The small, free-floating colonies, surrounded by a distinct 

 mucilage-envelope, were in general roughly spherical, but sometimes 

 of irregular outline (diam. of spherical colonies, 18-30 /a ; dimensions 

 of elongated colonies, 27 x 21, 33 X 24, 48 x 24 /a) ; occasionally it 

 looked as though such colonies were breaking up into smaller ones. 

 The cells were minute (diam., 15-3 /a), spherical or slightly oval, and 



* This is also the case in specimens of this species (J. E. Tilden, S. Pacific 

 Algae, No. 3) examined at the British Museum : they differ only in the smaller 

 size of the cells. 



