OF THE THIRD TANGANYIKA EXPEDITION. 133 
147. PEDIASTRUM DUPLEX, Meyen, Beob. Algenf. (1829) p. 772 ; Lagerh. 
in Ofvers. К. Vet.- Аай. Fórh. (1882) no. 2, p. 56.—P. pertusum, Kiitz. 
Phye. Germ. (1845) p. 143 (ex parte). Р. Napoleonis, Лаз, Brit. Desm. 
(1848) р. 186, t. 31. fig. Те, e. 
Nyasa.—Swampy lake margin, Domira Bay (19 June, 1904 ; no. 579). 
Tanganyika. —Plankton, near Baraka (24 Feb. 1905 ; no. 240). 
Forma cellulis centralibus ut in forma rectangulari, cellulis periphericis 
cum processibus divaricatis valde attenuatis; membrana cellularum granulata. 
Diam. cænob. 160-235 ш ; diam. cell. 29-33 p. 
Victoria Nyanza.—Plankton, near Bukoba (20 Apr. 1905 ; no. 252). 
This form resembles forma coherens, Bohlin, and forma rectangulare, Bohlin 
(in Bih. К. Sv. Vet.-Akad. Handl. xxiii. no. 7 (1897), p. 31, t. 2. figs. 1-3). 
in the form of the central cells, but differs in its peripheral cells. 
Var. GLATHRATUM, А. Br. Alg. Unicell. (1855) p. 93. 
Victoria Nyanza—Plankton, near Bukoba (21 Apr. 1905; no. 252). 
Among Utricularia, near Entebbe (1 May, 1905 ; no. 620). 
Tanganyika.—In swamp, Mbete (28 Oct. 1904 ; no. 108). 
Var. RETICULATUM, Lagerh. in Ofvers. К. Vet.-Akad. Förh. (1882) no. 2, 
p. 56, t. 2. fig. 1. 
Victoria Nyanza.—Among Utricularia, near Entebbe (1 May, 1905; 
n. 620). 
Tanganyika.— п swamp, Mbete (no. 108). 
148. PEDIASTRUM SIMPLEX, Meyen, 1. с.; Menegh. in Linnea, xiv. (1840) 
p. 212; Rabenh. Fl. Europ. Alg. hi. (1868) p. 71; Wildeman, т Bull. de 
l Herb. Boissier, i. (1893) р. 412, t. 9; Chodat, Algues Vertes de la Suisse 
(1902), p. 225 е. fig.—P. simplex, cf. Reinsch, Algenfl. Frank. (1867) p. 88, 
t. 7. fig. 4 a, В. P. simplex a. compactum, Chodat, l. c. 
Peripheral cells produced outwardly into a long attenuated process, outer 
margins of cells concave ; central cells polygonal, either without intercellular 
spaces, or with minute spaces between some or all of the cells. Processes 
radiating, generally rather delicate but sometimes stout, apices minutely 
truncate or nearly emarginate ; cell-walls commonly punctate and sometimes 
granulate. 
Diam. соепоЪ. 44-92 ш; diam. cell. 9-16 р. 
Nyasa.—Plankton, Anchorage Bay (13 and 14 June, 1904 ; nos. 9 and 10). 
Tanganyika.—In plankton, near Chamkaluki (15 Nov. 1904; по. 160) 
and near Baraka (24 Feb. 1905 ; no. 240). 
Forma 8тгвми.—Р. Sturmii, Reinsch, l. с. p. 90, t. 7. fig. І. P. Sturmii, 
rar. radians, Lemm. Forschungsb. Biol. Stat. Plón, vii. (1899) p. 20. 
Outer margins of peripheral cells convex ; central cells generally without 
intercellular spaces, but sometimes with small ones. 
Diam. сопор. 20-82 ш; diam. cell. 8-17 p. 
