Contributions to Our Knowledge of the Fresliivater Algae of Africa. 67 
2. Anahaena torulosa (Carm.), Lagerlieim, Bidr. Sv. Algfl., Oefvers. K. 
Vet.-Akad. Foerhandl., 1883, No. 2, p. 47 ; Bornet et Flahault, op. cit., 
p. 236. 
Sample 324 (rare, on surface of PJiormidium fragile) . 
Diani. cell., 4*5 ; diam. lieterocyst., 6fi; lat. spor., 6-7*5 ; long, 
spor., 15-18 fi. Spores contiguous to lieterocysts, often somewhat hour-glass- 
shaped. This species does not appear to be very sharply distinguished from 
A. catenula (Kuetz.), Bornet et Flahault. 
(Note. — An indeterminable species of Anahaena was also observed in 
sample 327.) 
(3) SCYTONEMATACEAE. 
aENUs SCYTONEMA Agardh. 
1. Scytoneina sp. {stuposum (Kuetz,), Bornet?). 
Sample 327. 
Diam. fil., 21-27 diam. trich., 18-20 Heterocysts flattened, some- 
times hour- glass-shaped ; cell-contents often violet. The material was 
inadequate for satisfactory determination. 
(4) STIGONEMATACEAE. 
Oenus STIGONEMA Agardh. 
1. Stigonema turfaceum (Berkeley), Cooke, Brit. Freshw. Alg., 1882-84, 
p. 272, PL CXI, fig. 2 ; Bornet et Flahault, op. cit., ser. 7, v, 1887, p. 74. 
Sample 36 (rare). 
Diam. fil., 33 /i. 
(5) RIVULARIACEAE. 
Genus CALOTHEIX Agardh. 
1. Calothrix gracilis, F. E. Fritsch, Freshw. Alg., in Rep. Nat. Antarct. 
Exped., vi, 1912, p. 37, PI. Ill, figs. 164-172. 
Yorm^ flexuosa, n. f. (Fig. 28). 
Fills plerumque valde flexuosis, gregariis, cellula apicali saepe subacuta. 
Diam. fil. ad bas., 6-7 ; diam. trich. ad bas., 5-6 jj. ; diam. fil. in media 
parte, 4-5 fi ; diam. trich. in media parte, 3-3'5 ix ; diam. lieterocyst., 5-6 ^ ; 
diam. spor. immatur., 6 fx, long., 9 
Sample 327 (common as an epiphyte on fragments of water-plants and 
on filament^ with zvgospores of Spirogyra hellis). 
