HOW TO KNOW THE FRESH- WATER ALGAE 



Fig. 334. Navicula sp.; a, top (valve) view; b, side (girdle) view. 



Figure 334 



Fig. 335. Gomphonema sp. 



Figure 335 



Fig. 336. Surirella splendida (Ehr.) Kuetz. 



Fig. 337. Cocconeis Pediculus Ehr. 



Figure 336 



Figure 337 



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