FIGURES 19–23 in Stephanodiscus Ehr. species from Holocene sediments in the Faiyum Depression (Middle Egypt)

FIGURES 19–23. Stephanodiscus galileensis, LM. Fig. 19. Convex valve showing a distinct sub-marginal hyaline ring in focus. Fig. 20. Similar showing marginal ring of spines and valve central area in focus. Fig. 21. Concave valve showing finer fascicle structure (see S. galileensis morphotype B, Hakansson & Locker 1987) and valve face fultoportulae (arrowed). Fig. 22. Similar showing valve central area in focus. Fig. 23. Similar, but valve is more strongly silicified. Scale bars = 5 µm (Figs 19–23).