1, 2 Navicula cryptocephala (6955) 3 Navicula seibigiana (6956) 4 Navicula cryptotenella (6955) 5, 6 Navicula angusta (6957, 6958) 7 Navicula libonensis (6955) 8 Caloneis silicula (6957) 9, 10 Caloneis falcifera (6955) 11 Caloneis tenuis (6957) 12–15 Hygropetra balfouriana (6957) 16 Navicula vulpina (6957) 17 Navicula radiosa (6957) 18 Navicula lanceolata (6958) 19–21 Navicula subconcentrica (6955, 6956) 22, 23 Caloneis thermalis (6955) 24, 25 Caloneis alpestris (6955, 6957). Scale bar: 10 µm.