Contributions to Our Knowledge of the Freshwater Algae of Africa. 2S 
Samples 158 (common), 159 (rare). 
The individuals of this species, named after the collector, usually occurred 
in more or less extensive groups comprising any number of cells up to 50, 
arranged approximately parallel to one another and in close juxtaposition. 
The general shape of the cell (Fig. 6, B) is not unlike that of C. leibleinii^ 
Kuetz., but the ends are altogether different, being obliquely truncated,, 
more or less markedly thickened, and provided with a characteristic excavation 
of the membrane of varying depth (Fig. 6, a, h). The cell- wall, although 
apparently colourless when first secreted, very soon takes on a reddish or 
brownish-red tinge ; in a few cases it showed a very fine granulation. The 
cells are provided with a varying number of median sutures (Fig. 6, B). 
The contents invariably included a large number of big starch grains, which 
made it impossible to decipher the chloroplast ; a single axial series of 
pyrenoids, however, seems to be present. 
There is some resemblance between this species and C. excavatum, Borge 
(" Suesswasseralg. aus Suedpatagonien," ' Bih. K. Sv. Vet.-Akad. Handl.,' 
xxvii, Afd. Ill, No. 10, 1901, p. 19, Tab. II, figs. 7-9) ; in the latter, however, 
the ends are different, the membrane is apparently colourless, and there are 
no median sutures. 
2. Closterium parvuhim,^Siegeli, Gratt. einzell. Algen., 1849, p. 106, Tab. 
YI, C, fig. 2 ; W. & a. S. West, loc. cit., p. 133, PI. XV, figs. 9-12. 
Samples 36, 338, 339, 340. 
Dist. inter apic, 112-135 /x; lat., 11-13 fx. 
Previously recorded from Cape Colony (Fritsch). 
var. angustum, W. & G. S. West, loc. cit., p. 134, PI. XV, figs. 13, 14. 
Samples 338, 339, 340. 
Dist. inter apic, 93-96 /x ; lat., 6 /x. 
3. Closterium leihleinii, Kuetz. ; W. & Gr. S. West, loc. cit., p. 141, 
PI. XVI, figs. 9-14. 
Sample 315. 
Long., 208 /x; lat., 35 /x. 
Previously recorded from Little Namaqiialand (Gr. S. West), from 
Madagascar (Fritsch), and Cape Colony and Orange Free State (Fritsch). 
4. Closterium moyiiliferum (Bory), Ehrenb. ; W. & Gr. S. West, loc. cit., 
p. 142, PI. XVI, figs. 15, 16. 
Samples 26, 35, 64, 65, 85, 312, 327, 334, 336, 337. 
Previously recorded from Little Namaqualand (Gr. S. West) and Cape 
Colony (Fritsch). 
5. Closterium ehrenhergii, Menegh. ; W. & Gr. S. West, loc. cit., p. 143, 
PI. XVII, figs. 1-4. 
