FIGURES 64–68 in Observations on Hippodonta (Bacillariophyceae) in selected ancient lakes

FIGURES 64–68: SEM micrographs. Figs 64–66. Hippodonta latelanceolata (type material). Fig. 64. External view of entire valve. Terminal pores of raphe deflected towards secondary valve side. Fig. 65. Close-up of central area of valve in Fig. 64. Central raphe endings with pronounced teardrop-shaped depressions. Fig. 66. External view of valve depicting complete mantle. Pronounced hyaline area present throughout valve mantle. Fig. 67. Hippodonta lueneburgensis. External view of complete frustule showing broad unornamented girdle. Fig. 68. Hippodonta costulatiformis var. costulatiformis. External view of complete frustule showing prominent hyaline area present on valve mantle and broad, unornamented girdle. Scale bars in Figs 64, 66, 68 = 5 µm; Fig. 67 = 10 µm; Fig. 65 = 2 µm.