FIGURES 1–8 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 1–8. Pyrgodiscus armatus Kitton ex Cleve. 1, 4. Reproduction from Cleve 1885: pl. 13, fig. 13a–b. 2, 5. Reproduced from Witt 1885: 30, pl. VI, figs 7, 8. 3, 6. Reproduction from Schmidt 1886: pl. 92, figs 15, 16. 7, 8. LM of Pyrgodiscus armatus: BM 46649, Sturt A1588, d= 85 µm; cdw = 43 µm; sp = 29µm. Scale bar = 10 µm (Figs 7, 8).