148 MR. G. S. WEST ON THE FRESHWATER ALGAE 
Family COSCINODISCACEZ. 
Genus CYCLOTELLA, Kutz. 
191. CYCLOTELLA COMPTA, ( Ehrenb.) Kütz. Sp. Alg. p. 20 (1849). 
Victoria Nyanza.—In plankton, Bukoba (18 Apr. 1905 ; no. 249). 
e 
192. CYCLOTELLA MENEGHINIANA, Kütz. Вас. р. 50 (1865). 
Var. RECTANGULATA, Grun. ; Van Heurck, Syn. Dat. Belg. t. 94. figs. 17-19. 
Diam. valv. 15 д. 
Nyasa.—In scrapings from bottom of s.s. * Guendolen ' at anchor S. end of 
lake (15 June, 1904 ; no. 577). 
193. CYCLOTELLA OPERCULATA, Kütz. l. е. 
Nyasa.—In plankton, Anchorage Bay (11-14 June, 1905; nos. 5, 9, and 
10) and Monkey Вау (18 June, 1904 ; no. 16). 
Tanganyika.—In plankton, near Kala (19 Nov. 1904; no. 170). 
194. CvcLoTELLA KüTZINGIANA, Chauvin; Thw. in Aun. Mag. Nat. Hist. 
ser. 2,1. (1848) p. 169; Van Heurck, 1. c. $. 94. figs. 1, 46. 
Nyasa.—In plankton, Anchorage Bay (14 June, 1905 ; nos. 9 and 10). 
Tanganyika.—On surface of swamp, Toa (10 Jan. 1905 ; no. 208). 
Victoria Nyanza.—In plankton, near Bukoba (21 Apr. 1905 ; no. 252). 
Genus STEPHANODISCUS, Ehrenb. 
195. STEPHANODISCUS Astraa, (Johrenb.) Grun, in Cleve $ Grun. Aret. 
Diat. 114 (1880); Van Heurck, Syn. Dat. Belg. (1885) i. 95. fig. 5. 
Nyasa.—In plankton, Anchorage Bay (11-14 June, 1904; nos. 5, 9, 
and 10). On shore, Domira Day (19 June, 1904; no. 17). On rocks, 
Nkata Вау (23 June, 1904 ; по. 23). In plankton, off Vahambwera Point 
(24 June, 1904 ; no. 24). 
Some finely developed specimens of this Diatom were observed, the valves 
attaining a diameter of 81 р. 
Var. SPINULOSUS, Grun.; Van Heurck, l. с. t. 95. fig. 6. 
Nyasa.—In plankton, Anchorage Bay (14 June, 1904 ; no. 10); also Deep 
Bay (24 June, 1904 ; no. 25). 
Var. MINUTULUS, ( Aitz.) Grun.: Van Heurck, 1. c. t, 95. figs. 7, 5.— Cyclotella 
minutula, Кш. 
Nyasa.—In plankton, Anchorage Вау (11-14 June, 1904; поз. 5, 9 
and 10). 
