OF THE THIRD TANGANYIKA EXPEDITION. 109 
36. CLOSTERIUM Venus, Айс. Phye. Germ. (1845) p. 1305 W. & G. S. 
West, Brit. Desm. 1. (1904) p. 137, t. 15. figs. 15-20. 
Lat. 85 и; apicibus 72 р inter se distantibus. 
Nyasa.—In swamp, Karonga (2 July, 1904 ; no. 34). 
Tanganyika.—In plankton, Lofu River (5 Oct. 1904 ; no. 123). 
37. ČLOSTERIUM Главтетхи, Küt:. in Linnea, viii. (1833) p. 596; И, $ 
G. S. West, l. с. p. 141, t. 16. figs. 9-14. 
Nyasa.—Among Algæ growing on stones, Domira Bay (19 June, 1904 ; 
по. 17). Among Utricularia, Domira Вау (19 June, 1904 ; no. 579). 
Victoria Nyanza.—In pools near the shore, Bukoba (20 Арг. 1905; 
no. 251). 
Tanganyika.—In swamp, Mbete (28 Sept. 1904 ; no. 108). In plankton, 
Baraka (24 Feb. 1905 ; no. 240). 
38. CLOSTERIUM MONILIFERUM, (Bory) Ehrenb. Infus. p. 91 (1838) ; Ваз, 
Brit. Desm. (1848) p. 166, t. 28. fig. 3; W. $ G. S. West, l c. p. 142, 
t. 16. figs. 15, 16. 
Var. GALICIENSE, (Gutw.) nob. Closterium galiciense, G'utw. in Rospraw. 
matem.-przy. Akad. Umiej. Krakow. (1896), p. 39, t. 6. fig. 18. 
Long. 248-294 р; lat. 44—47 u; lat. apic. 11-12 р. 
Victoria Nyanza.—In pools near the shore, Bukoba (20 Apr. 1905; no. 251). 
The African plants possessed a smooth and colourless cell-wall, and agreed 
perfectly in size and general proportions with Gutwinski's Galician examples. 
The distinctive features from typical C. moniliferum are the thickened apices 
of the cells and the reduced ventral inflation. 
39. CLOSTERIUM ACEROSUM, (Schrank) Ehrenb. Infus. p. 92 (1838); Ка}, 
Brit. Desm. (1848) р. 164, t. 27. fig. 2; W. & G.S. West, l.c. p. 146, t. 18. 
figs. 2—9. 
Nyasa.—Among other Algæ on the shore, Domira Day (19 June, 1904 ; 
по. 17). Among Utricularia, Domira Вау (19 June, 1904 ; no. 579.) 
Tanganyika.—In swamp, Toa (10 Jan. 1905 : no. 208.) 
40. CLosTERIUM TUMIDUM, Johnson, т Bull. Torr. Bot. Club, xxii. (1895) 
р. 291, t. 239. fig. 4; W. $ G. 5. West, Lc. p. 156, t. 19. figs. 15-18. 
Rather stout forms: long. 116-142 ш; lat. 19-20 ш; lat. apie. circ. 5 р. 
Victoria Nyanza.—In pools near the shore, Bukoba (20 Apr. 1905; no. 251). 
41. CLosTERIUM GRACILE, Breb. List Desmid. p. 155 (1856); И’. $ (G.S. 
West, 1. е. p. 166, t. 21. figs. 8-12. 
Tanganyika.—In swamp, Mbete (28 Sept. 1904 ; no. 108). 
