Contributions to Our Knowledge of the Freshwater Algae of Africa. 11 
2. Pediastrum integrum, Naegeli, oj:). cit., pp. 96, 97, Tab. V, b, fig. 4. 
var. ^earsoni (G. S. West), F. E. Fritscli. (Syn. : P. pearsoni, Gr. S. 
West, Fresh w. Algae, Percy Sladen Memorial Exped., etc., Ann. S. Afr. 
Mus., ix, 1912, p. 79, figs. 30-32.) (Fig. 3.) 
Samples 159, 311, 312, 314, 315 (especially common in 312). 
An examination of the extensive material in the present samples has 
shown that P. pearsoni is not sufiiciently distinct from P. integrum to 
Fig. 3. — Pediastrum integrum, Naeg., var. pearsoni {G. S. West), F. E. Fritsch. 
c in side view ; in g the cliloroplast and scrobiculation of the cell- wall are 
shown; in d the superincumbent cells are shaded. /, young colony {?). 
All figures x 600. 
warrant the establishment of a separate species. The only marked points 
of difference are : (a) the subcapitate character of the short processes borne 
by the marginal cells — a feature which is not always pronounced (cf. Fig. 3, 
a and d) ; (b) the fact that these processes are not situated in the same 
plane (cf especially fig. 3, c and West's fig. 31) ; (c) the minute scrobicula- 
tion of the membrane. As minor points of difference may be noted the 
not uncommon elliptical shape of the cells (Fig, 3, e, and West's fig. 30). 
