FIGURES 9–15 in Notes on the diatom collection of the Natural History Museum, London (BM) VII: An account of some original specimens of Pyrgodiscus (Bacillariophyta) with notes on Stephanogonia (Bacillariophyta)

FIGURES 9–15. Pyrgodiscus armatus Kitton ex Cleve LM. 9, 10. BM 7333, d= 78 µm; cd = 26 µm; sp = 29 µm. 11, 12. BM 7334, d= 72 µm; sp = 30 µm. 13–15. BM 7334, d= 73 µm; cd = 28 µm; sp = 32 µm. Scale bars = 10 µm (Figs 9–12), 20 µm (Figs 13–15).