138 MR. С. S. WEST ON THE FRESHWATER ALGJE 
Subfam. SELENASTRE.X. 
Genus SCENEDESMUS, Meyen. 
156. SCENEDESMUS BIJUGATUS, ( Turp.) Kütz. Synops. лай. (1834).— 
Achnanthes bijuga, Turp., 1828. Scenedesmus obtusus, Meyen, 1829. 
Nyasa.—In swamp, Kota Kota (20 June, 1904; no. 18). Swampy lake 
margin, Domira Bay (19 June, 1904 ; no. 979). 
Tanganyika.—Plankton, off Niamkolo Island (29 July, 1904 ; no. 36). 
On the stones of the shore, Niamkolo (3 Aug. 1904 ; no. 44). Plankton, 
Komba Вау (11 Oct. 1904; no. 135) and near Sumbu (13 Oct. 1904 ; 
no. 138). In swamp, Toa (10 Jan. 1905 ; no. 208). 
Forma ARCUATA, (Lemm.) W. & G. S. West, in Trans. Roy. Irish. Acad. 
xxxiii. sect. В (1906), р. 105, t. 10. figs. 12-14.—Scenedesmus arcuatus, 
Lemm. in Forschungsb. Biol. Stat. Plön, vii. (1899) p. 17, t. 1. figs. 2-4. 
Tanganyika.—Plankton, Komba Вау (11 Oct. 1904; no. 135) and near 
Chamkaluki (15 Nov. 1904 ; по. 160). 
This form appears to be frequent in the plankton. Several colonies were 
observed (from no. 160) attached together to form a curved plate of oblong 
cells, which greatly resembled a colony of Crucigenia rectangularis, (Nüg.) 
F. Gay, var. irregularis, (Wille) nob. 
157. ScENEDESMUS DENTICULATUS, Lagerh. in Ofvers. К. Sv. Vet.-Akad. 
Fork. (1882) no. 2, p. 61, t. 2. figs. 13-16. 
Var. LINEARIS, Hansg.in Archiv Naturwiss. Landesdurchf. Войт. vi. (1888) 
no. 6, p. 268.—S. denticulatus, var. lineatus, West, in Journ. Linn. Soc., Bot. 
xxix. (1892) p. 193, t. 18. fig. 7. 
Муава.—Оп stones on shore, Domira Bay (19 June, 1904 ; no. 17). In 
swamp, Kota Kota (20 June, 1004 ; no. 18). In swamp, Karonga (2 July, 
1904 ; no. 34). 
Tanganyika.—Plankton, Lofu River (5 Oct. 1904 ; no. 123). 
158. ScENEDESMUS ACUTIFORMIS, Schröder, in Forschungsb. Biol. Stat. Plön, 
v. (1897) p. 17, t. 2. f. 4. 
Nyasa.—In pools, Nkata Bay (23 June, 1904 ; no. 22). Swampy lake 
margin, Domira Bay (19 June, 1904 ; no. 579). 
Var. BRASILTENSIS, (Bohlin) W. $ G. 5. West, in. Trans. Bot. Soc. Edinb. 
xxiii. (1905) p. 30, t. 1. figs. 8, 9.—8. brasiliensis, Bohlin, т Bih. K. Sr. 
Vet.- Akad. Handl. xxiii. (1897) no. 7, p. 22, t. 1. figs. 26-27. 8. acutiformis, 
Schród. var. spinulifer, W. & G. S. West, in Bot. Tidsskr. xxiv. (1901) 
p- 182, t. 4. figs. 46-49. 
Nyasa.—On rocks and in shore-pools, Nkata Bay (23 June, 1904 ; nos. 22 
