Plate VII. 
Figs. 1, 2,—Cosmarium moniliforme, Turp. 
Fig. 3.—Cosmarium moniliforme. After division, new semi-cells enlarged. 
Fig. 4.—Cosmarium moniliforme. Zygospore. 
Figs. 5, 6, 7.—Cosmarium Blyttii. Front, side, and end views. 
Figs. 8, 9.—Euastrum compactum, Wolle. 
Figs. 10, 11.—Staurastrum Bienneanum, var. ellipticum, Wille. 
Figs. 12a, 12d.—Cosmarium Portianum. Living fronds. 
Figs. 12, 12c,—Cosmarium Portianum. Empty fronds. 
Fig. 12e.—Cosmarium Portianum. End view. 
Fig- 12f.—Cosmarium Portianum. Zygospore. 
Figs, 18a, 13.—Cosmarium botrytis. Living fronds. 
Figs. 13c, 13d.—Cosmarium botrytis. Empty fronds. 
Fig. 13e.—Cosmarium botrytis. End view. 
Fig. 13f.—Cosmarium botrytis. Side view. 
Fig. 139.—Cosmarium botrytis. Zygospore, 
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