FRESHWATER ALGA. 21 
cellularum contracto, cum pyrenoide magno globoso in utraque parte cellule ; 
chromatophoram non vidi. 
tones cell) — 135). lat. cell) = 1167p. 
Hab.—Isolated among sediment from freshwater ponds, Granite Harbour, 
January 20th, 1902. 
The discovery of this Desmid is of great interest, as it indicates that the group 
is not quite unrepresented, even in these extreme southern latitudes. It may well be 
that the form just described is new, but the material was too scanty and the 
cell-contents too badly preserved to warrant the establishment of a new species. The 
cells appear elliptical in shape and have somewhat flat rounded ends. There is a 
slight constriction in the middle of the cell, as in many species of the genus. The 
specimens show considerable resemblance to P. cruciferum (De Bary) Wittr. (¢/. 
W. and G. 8. West, A monograph of the British Desmidiacee, Ray Society, 1904, 
Wola ls) p: 100, Bl X.; figs: 18, 19), but the shape of the cell is rather different. The 
contents were contracted in all the individuals seen, and no details of the chloroplast 
could be made out; each half of the cell however has a large circular pyrenoid. In 
many cases the contents showed a faint constriction similar to that of the cell-wall. 
CYANOPHYCHA (MYXOPHYCEAS). 
CHROOCOCCACE/E. 
Genus CHroococcus Nigeli. 
15. CHRoococcus TURGIDUS. 
Chroococcus turgidus (Kiitz.) Niig., Gatt. einzell. Alg. (1849), p. 46. 
Diam. cell. = 13-14 p. 
Hab.—Gap pond, Winter Harbour, February 20th, 1904 (on Phormidium). 
The sheath was plainly stratified, thus distinguishing this form from C. ininutus, 
which was much more abundant. 
16. CHROOocOccUS MINUTUS. 
Chroococcus minutus (ktitz.) Niig., op. cit., p. 46; Rabenhorst, Fl. Europ. Alg., ii. (1865), p. 30. 
Diam. cell. = 8-11 or sometimes even 13 p. 
Hab.—Abundant on the surface of Phormidium in some of the material from the 
Gap pond, Winter Harbour. 
These specimens, like those recorded by Messrs. West (op. cit., p. 297) are larger 
than the normal; the cells were often grouped to form colonies of appreciable size. 
