FIGURES 24–33. Pyrgodiscus simplex Witt. 24. Reproduced from Witt 1885 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 24–33. Pyrgodiscus simplex Witt. 24. Reproduced from Witt 1885: 30, pl. VI, fig. 6. 25. Reproduced from Schmidt 1886: pl. 100, fig. 13. 26–29. BM 64641 eX Barker 185, d = 54 μm, cdw = 34 μm; 30–33. BM 65879 eX FergUsOn, d = 44 μm, cdw = 31 μm. Scale bars = 5 µm (Figs 26–29), 10 µm (Figs 27–33).