OF THE THIRD TANGANYIKA EXPEDITION. 143 
174. TETRABDRON REGULARE, Käte. Phyc. Germ. (1845) p. 129.—Poly- 
edrium tetraédricum, Nig. Gatt. епс. Alg. (1849) p. 84, t. 4 в. fig. 3. 
Diam. cell. sine spin. 18-26 д. | 
Nyasa.—In swamp, Karonga (29 June, 1904 ; по. 32, and 2 July, 1904 ; 
по. 34). 
175. TETRAEDRON LOBULATUM, (Näg.) Hansg. т Hedwigia, xxvii. (1888) 
p. 132.— Polyedrium lobulatum, Ndg. Gatt. einz. Alg. (1849) p. 84, t. 4 в. fig. 4. 
Victoria Nyanza.—Among Utricularia, near Entebbe (1 May, 1905; 
no. 620). 
176. TETRAEDRON BiFURCUM, ( Wille) Lagerh. in Nuova Notarisia (1893), 
p. 160.—Polyedrium trigonum f. bifurcum, Wille, in Bih. К. Sv. Vet.- Akad. 
Нап. viii. (1884) no. 18, р. 12, t. 1. fig. 24. 
Victoria Nyanza.—Swampy pool near Bukoba (20 Apr. 1905 ; no. 618). 
Tanganyika.—In swamp, Kituta (23 Aug. 1904 ; no. 72). 
Genus CERASTERIAS, Reinsch. | 
177. CERASTERIAS RHAPHIDIOIDES, Reinsch, т Abh. Naturh. Ges. Nirnb. 
iii. (1867) p. 68, t. 5. fig. 1. 
Diam. cell. (cum radiis) 48-60 д. 
Tanganyika.—Plankton, near Chamkaluki (15 Nov. 1904; no. 160) and 
near Kala (19 Nov. 1904 ; no. 170). 
Subfam. PHYTHELLIE Æ. 
Genus RICHTERIELLA, Lemm. 
178. RICHTERIELLA BOTRYOIDES, (Schmidle) Lemm. in Hedwigia, xxxvii. 
(1898) p. 306, t. 10. figs. 1-6.—Golenkinia botryoides, Sehmidle. Richteriella 
globosa, Lemm. 
Forma QUADRISETA, (Lemm.) Chodat, 1902.—R. quadriseta, Lemm. l. e. 
p. 307, t. 10. fig. 7. 
Tanganyika.—Plankton, near Kala (19 Nov. 1904 ; no. 170). 
Genus CHODATELLA, Гетт. 
179. CHODATELLA SUBSALSA, Lemm. in Hedwigia, xxxvii. (1898) p. 310.— 
Lagerheimia subsalsa, Lemm. in Forschungsb. Biol. Stat. Plön, vi. (1898) 
t. 5. figs. 2-6. 
Long. cell. (sine acul.) 5-13 р; lat. cell. 2:5—8'5 ш; long. acul. 7:5-26 д. 
Tanganyika.—In plankton, near Kala (19 Nov. 1904 ; no. 170). 
This Alga was fairly frequent in one of the plankton collections from 
Tanganyika (no. 170), but was not observed from any of the others. The 
