PLATE 27 

 FIG. PAGE 



STAURONEIS Continued 



1 Stauroneis phcenicenteron Ehr 88 



2 Stauroneis acuta Wm. Sm 89 



3 Stauroneis americana A. S 89 



4 Stauroneis anceps var.? 88 



5 Stauroneis anceps var. gracilis (Ehr.) Cl 88 



6 Stauroneis salina Wm. Sm 89 



7 Stauroneis anceps var. amphicephala (Kuetz.) Cl 88 



8 Stauroneis anceps var.? 88 



9 Stauroneis anceps var.? 88 



10 Stauroneis crucicula (Grun.) Cl 89 



1 1 Stauroneis smithii Grun. . . 89 



NAVICULA 



12 Navicula lacustris Greg 92 



13 Navicula hasta Pant 97 



14 Navicula hasta var. punctata n. var 97 



15 Navicula punctata var. asymmetrica Lagerstedt 92 



16 Navicula dicephala Wm. Sm 96 



17 Navicula placenta Ehr 94 



18-19 Navicula inflexa Greg 96 



20 Navicula pinnata Pant.? 96 



21 Navicula oblonga Kuetz 97 



22 Navicula pennata A. S 96 



23 Navicula pygmaea Kuetz 94 



24 Navicula humilis Donk. . 96 



