514 Annals of the Smith African Museum. 



Genus ANKISTRODESMUS Corda. 

 (RHAPHIDIUM Kuetz.) 



1 . . 1 nkisirodesm us falcatus (Corda), Balfs, Brit. Besin., 1848, p. 180. 

 (Syn. : Bhaphidium fasciculatum, Ivuetz. ; 11. polymorphism, Fresen., 

 var. falcatum, Babenh.) 



Samples 14, 31, 39, 48. 



Var. spirilliformis, Gr. S. West, Brit. Freshw. Algae, 1904, p. 224. 

 (Syn. : Rhaphidium polymorphum, Fresen., var. spirale, W. & G. S. 

 West, Notes on Freshw. Alg., I, Journ. But., xxxvi, 1898, p. 6.) 



Samples 14, 32, 39. 



Addendum : Genus of doubtful position. 



PLEUEOCOCCUS, Menegh. 



1. Pleurococcus antarcticus, W. & G. S. West, emend. F. E. Fritscli. 

 Freshw. Alg;., National Antarct. Exped., Nat. Hist., VI, 1912, 

 p. 13. 



Forma simplex, F. E. Fritsch, he. cit., p. 14, PI. I. figs. 30, 31, 33. 



Sample 42 (among Cyanophyceae). 



Diam. cell., 16-25 /a; crass, membr., 1'5-2'5/a. Quite typical 

 specimens, with a thick, indistinctly stratified membrane and the 

 usual oil- drops. The cells were without pyrenoids. 



2. Pleurococcus Jcoettlitzii, F. E. Fritsch, loc. cit., p. 15, PI. I, figs. 

 30-42. 



Sample 15 (on surface of Phormidium valderianum, rather rare). 



The discovery of this and the preceding species, both hitherto known 

 only from the Antarctic, in other parts of the Southern Hemisphere 

 is of some interest. The cells showed similar groupings, the same 

 distribution of fat. and the same dimensions as in the Antarctic 

 specimens. Oval cells were very common, and in a few cases the 

 contents were reddish (c/". loc. cit.). 



