168 MR. G. 5. WEST ON THE FRESHWATER ALGJE 
I think Schmidle's genus Myzoderma must be regarded as synonymous 
with Nostochopsis, Wood. The only difference is in the form of the thallus, 
which is expanded in the one case (N. G'oetzei) and more or less rounded in 
the other (N. lobatus), and to my mind this is not sufficient as а generic 
distinction. One of the most distinctive features of Nostochopsis is the lateral 
and often stalked condition of the heterocysts, and this is the same in each 
case. N. lobatus, Wood, is known to occur in Central Africa (vide W. & G. S. 
West, in Journ. Bot. xxxiv. (1896) p. 381, t. 361. figs. 1, 2; op. cit. xxxv. 
(1897) p. 264) ; and №. Goetzei differs from it in the more expanded thallus 
and consequent laxer disposition of the filaments, which in their inferior part 
are not arranged in parallel bundles, 
Family SCYTONEMACEZ. 
Genus SCYTONEMA, Aq. 
283. SCYTONEMA MIRABILE, (Dillw.) Born. in Bull. Soc. Bot. Fr. xxxvi. 
(1889) p. 155 in obs.— Conferva mirabilis, Dillw. Scytonema figuratum, Ag. 
Syst. Algar. 1824, р. 38; Born. & Flah. in Ann. Sci. Nat. 7° sér., Bot. v. 
(1887) pp. 101-3. 
Tanganyika.—In swamp, Kituta (23 Aug. 1904 ; по. 12). 
284. SCYTONEMA CRISPUM, ( Ад.) Born. І. c. р. 156 in obs.—Lyngbya crispa, 
Ag. (pro parte). Seytonema cincinnatum, (Kütz.) Thur. in Ann. Sci. Nat. 
6° sér., Bot. i. (1875) p. 380 ; Born. & Flah. l.c. (1887) p. 89. 
Nyasa.—On rocks at water-level, Deep Bay (25 June, 1904 ; no. 26). 
Tanganyika.— Among other Algz scraped from bottom of Dr. Cunnington's 
dau (24 Jan. 1905 ; no. 217). 
Genus TOLYPOTHRIX, Кг. 
285. TOLYPOTHRIX TENUIS, Kütz. Рус. Gen. p. 228 (1843); em. J. Schmidt, 
in Bot. Tidsskr, xxii. (1899) pp. 988 et 413.— /nclus. T. lanata, Wartmann, 
1858. 
Crass. fil. 11-14 д; crass. trich. 9-10 ш. 
Tanganyika.—In swamp, Kituta (23 Aug. 1904 ; no. 72). 
Г thoroughly agree with Schmidt (1. с. 1899) regarding the identity of 
Tolypothria tenuis, Kütz., and T. lanata, Wartm. 
Family NOSTOCACER. 
Genus NOSTOC, Vaucher. 
286. Nostoc PALUDOSUM, Айг. Tub. Phye. ii. (1850) p. 1, t. 1. fig. 2; 
=- 3 
Rabenh. Fl. Europ. Alg. ii. (1865) p. 164; Born. & Flah. l. e. (1888) 
p. 191. 
Nyasa.—In swamp, Karonga (2 July, 1904 ; no. 34). 
