110 МК. G. S. WEST ON THE FRESHWATER ALGJE 
Var. TENUE, (Гетт.) И”. $ G. S. West, in Trans. Linn. Soc. ser. 2, Bot. 
vi. (1902) p. 138, t. 18. figs. 22, 23.—С. limneticum, Lemm., var. tenue, Lemm. 
Victoria Nyanza.—Among Utricularia, near Entebbe (1 Мау, 1905; 
no. 620). 
42. OLosrERIUM ACUTUM, (Lyngb.) Breb. т Ralfs, Brit. Desm. (1848) 
р. 177, t. 30. fig. 5, t. 34. fig. ба, b, d-f ; И’. С. S. West, Brit. Desm. i. 
(1904) р. 177,t. 23. figs. 9-14. 
Lat. cell. 4-45 u ; long. zygosp. 32 ш; lat. max. zygosp. 18 y. 
Nyasa.—Among Utricularia, swampy margin of lake, Domira Bay (19 
June, 1904; no. 579). 
Tanganyika.—In swamp, Kituta, with zygospores (26 Aug. 1904 ; no. 80). 
43. CLOSTERIUM RaLrsu, Breb. т Ralfs, Brit. Desm. (1848) p. 17; Ralfs, 
l. с. p. 174, t. 20. fig. 2; W. & G. S. West, l. e. p. 182, t. 24. figs. 6, 7. 
Var. HYBRIDUM, /ФабепА. Fl. Europ. Alg. ii. (1808) p. 135; W. & G.S. 
West, l. c. p. 183, t. 24. figs. 8-12. 
Forma paullo crassior : long. 802-332 ш; lat. 42-45 р; lat. apic. 9-10 p. 
Victoria Nyanza.—In pools near the shore, Bukoba (20 Apr. 1905; no. 251). 
The specimens were rather broader than is usual for this frequent tropical 
Closterium, and in this respect they resembled a plant described by Gutwinski 
as C. Wage (vide Rospraw. matem.-przyr. Akad. Umiej. Krakow. 1896, 
р. 40, +. 2. fig. 20). The apices were also somewhat angular. It seems pro- 
bable that C. Wage is only an extreme shortened form of С. Ralfsii 
var. hybridum. 
Genus PLEUROTZENIUM, №. 
44. PLEUROTENIUM COoRONATUM, (Bréb.) Rabenh. Fl. Europ. Alg. iii. (1868) 
р. 148; W. & G. S. West, l. с. р. 199, t. 27. figs. 16-18, t. 28. fig. 4. 
Tanganyika.—In swamp, Kituta (23 Aug. 1904 ; nos. 72 and 80). 
45. PLEUROTÆNIUM suBcoRONULATUM, ( W. В. Turn.) 
in Trans. Linn. Soc. ser. 2, Bot. у. (1895) p. 44, t. 5. f. 33. 
Var. pgruM, W. $ G. 5. West, l c. (1896) р. 235, t. 13. figs. 2, 3. 
Long. 460 р; lat. ad bas. semicell. 40 и, ad apic. 35 p. 
Victoria Nyanza.—Among Utricularia in swampy pool near Bukoba (20 
Apr. 1905; no. 618). 
Borge has observed specimens from Brazil in which only one semicell 
possessed the infra-apical constriction (vide Arkiv fór Botanik, К. Sv. Vet.- 
Akad., Bd. i. (1903), p. 82). The curious ligature-like constriction of this 
variety was well marked in the examples from Victoria Nyanza, but it is 
possible that it is only a variation due to inequality of growth. 
W. у G.S. West, 
