FIGURES 24–30 in Stephanodiscus Ehr. species from Holocene sediments in the Faiyum Depression (Middle Egypt)

FIGURES 24–30. Stephanodiscus galileensis, LM. Fig. 25. External convex valve note irregular spines and sub-marginal silica ring. Fig. 25. Internal convex valve with rimoportula arrowed. Fig. 26. Detail of same valve showing central area ring of fultoportulae with two or three satellite pores. Fig. 27. External concave valve with ring of spines and raised interfascicular ribs. Fig. 28. Internal concave valve showing ring of sub-marginal fultoportulae and rimoportulae (arrowed). Fig. 29. Similar showing detail of a rimoportula, a submarginal fultoportula with two satellite pores and marginal fultoportulae. Fig. 30. Detail of a sub-marginal fultoportula with three satellite pores and surrounding domed cribra. Scale bars = 10 µm (Figs 24, 25, 27, 28), 1 µm (Figs 26, 29), and 0.5 µm (Fig. 30).