3 Navicula delawarensis Grun. 92 4-6 Navicula pusilla Wm. Sm. 91 5 Navicula humerosa Bréb. 91 7 Navicula spectabilis var. emarginata Cl. 94 8 Navicula pusilla var. subcapitata n. var. 91 9 Navicula punctulata Wm. Sm. 92 10 Navicula lyra Ehr. 93 11 Navicula hennedyi var. manca A. S. 93 12 Navicula hennedyi Wm. Sm. 93 13 Navicula lyra var. dilatata A. S. 93 14 Navicula yarrensis Grun. 101 15 Navicula yarrensis Grun. (smaller form) 101 16 Navicula yarrensis Grun. var.? 101 [Illustration: PLATE 25] PLATE 26 NAVICULA 1-2 Navicula cuspidata Kuetz. 100 3 Navicula cuspidata var. ambigua (Ehr.) Cl. 100 4 Navicula spicula (Hickie) Cl. 100 5 Navicula integra Wm. Sm. 99 6 Navicula mutica Kuetz. 97 8 Navicula americana Ehr. 98 9 Navicula pupula var. bacillarioides Grun. 98 10 Navicula bacillum Ehr. 98 11 Navicula semen Ehr. 98 12 Navicula atomus Nægeli. 100 13 Navicula minima Grun. 98 14 Navicula ramosissima (Ag.) Cl. 95 15 Navicula crucigera (Wm. Sm.) Cl. 100 16 Navicula viridula var. rostellata Kuetz. 95 17 Navicula radiosa Kuetz. 94 19 Navicula gracilis var. schizonemoides (Ehr.) V. H. 95 20 Navicula peregrina Ehr. 94 21 Navicula cyprinus (Wm. Sm.) 95 22 Navicula reinhardtii Grun. 95 23 Navicula lanceolata var. arenaria (Donk.) Cl. 95 24 Navicula salinarum Grun. 95 25 Navicula gastrum Ehr. 96 26 Navicula anglica Ralfs. 96 DIPLONEIS 7 Diploneis oculata (Bréb.) Cl. 86 STAURONEIS