The Freshwater Algae of Africa. 569 



II. HETEROKONTAE. 



(4) TRIBONEMACEAE. 



Genus OPHIOCYTIUM Naegeli. 



1. Ophiocytium majus, Naegeli, G-att. einzell. Algen, 1848, p. 89, 

 PI. IV, A, fig. 2 ; Heering, Suesswasseralg. Schleswig-Holsteins, etc., 

 i, 1906, p. 120, fig. 25. 



Sample 48. 



2. Ophiocytium parvulum (Perty), A. Braun, Alg. unicell., etc., 

 1855, p. 55 ; Heeviug, op. cit., p. 124, fig. 31. 



Sample 2 (very rare). 



3. Ophiocytium arbuscula (A. Braun), Rabenhorst, Fl. Europ. Alg., 

 etc., iii, 1868, p. 68; Heering, op. cit., p. 116, fig. 22. (Syn. : Scia- 

 <lii<m arbuscula, A. Braun.) 



Sample 21 (on Oedogonium sp.) 



Many of the individuals showed good stages in aplanospore-forma- 

 tion. 



Genus TRIBONEMA Derbes et Solier. 



1. Tribonema bombycinum, Derbes et Solier, Mem. sur q. points d.l. 

 physiol. d. algues, Suppl. aux Comptes rendues, i, 1856, p. 18; Heering, 

 op. cit., p. 131, fig. 36. (Syn. : Conferva bombycina, Ag.) 



Forma genuina, Wille. 



Samples 2, 7 (rare), 8, 9, 10. 



Forma minor, Wille. 



Samples 27, 46, 48, 50. 



III. OYANOPHYCEAE (MYXOPHYCEAE). 



(a) CHROOCOCCALES. 



(1) CHROOCOCCACEAE. 



Genus CHROOCOCCUS Naegeli. 



1. Chroococcus mi nut us (Kuetz.), Naegeli, Gatt. einzell. Algen, 1849, 

 p. 46 ; Forti, Sylloge Myxophycearum, 1907, p. 14. 

 Sample 42 (scattered among other Algae, rare). 



