FIGURES 23–31 in Morphology and taxonomy of Psammodiscus Round & Mann (Bacillariophyceae: Rhaphoneidales) with a description of the new species Psammodiscus calceatus

FIGURES 23–31. Psammodicus calceatus sp. nov. (SEM). Fig. 23. External view of theca; square (a) enlarged view in fig. 24; square (b) enlarged view in fig. 25. Fig. 24. Valve face and mantle, areolae (A) occluded by plated rotae (R) with 3–10 spokes (S). Note areolae elongate with small number of spokes at the mantle. Fig. 25. External opening of rimoportula (Ri). Fig. 26. External view of theca, square enlarged view in fig. 27. Fig. 27. Valve lacking small pore and rimoportulae. Fig. 28. Internal valve view, arrowhead indicating rimoportula (Ri). Fig. 29. Internal opening of rimoportula (Ri), areolae (A) occluded by plated rotae (R), spokes not seen in internal views. Fig. 30. Areolae (A) occluded by plated rotae (R) on valve face and mantle. Fig. 31. Lips of rimoportula (Ri). Scale bars = 10 µm (Figs 23, 26, 28), 1 µm (Figs 24, 27, 30), 0.5 µm (Figs 25, 31).