FIGURES 27–32. Figs. 27–28. Biddulphia spinosa, Fig. 27 in Diatoms (Bacillariophyta) From Artificial Substrates And Sediments In The Caribbean Sea Off Yucatan, Mexico

FIGURES 27–32. Figs. 27–28. Biddulphia spinosa, Fig. 27. LM external valve view. Fig. 28. SEM external view showing the valve and cingulum, spines, granules and external tube of labiate process. Fig. 28a. Detail of a corner showing an elevation with ocellus. Fig. 29. Triceratium balearicum. Fig. 30. Biddulphia spinosa. Figs. 31–32. Triceratium favus. Scale bar: fig. 28a = 1 μm, figs. 28–31 = 10 μm.