FIGURES 12–17 in Further studies on the species diversity of the marine planktonic diatom genus Skeletonema (Bacillariophyta) in the Mexican Pacific

FIGURES 12–17. Skeletonema grevillei, LM (12), SEM (13–16) and TEM (17). Fig. 12. A rather long chain of 8 cells, some of them dividing, containing two chloroplasts per cell. Fig. 13. Terminal part of a chain showing terminal and intercalary valves, siliceous ridges (small arrows) between face and mantle at the terminal valve, TF's, one TR (arrow), and broken IF's. Fig. 14. Intercalary valves with IF's fusing to those of sibling valve in 1:1 junction type, a short IR (arrow), and siliceous ridges (small arrows) around bases of IF's. Fig. 15. Terminal valve with fultoportulae (TF's) irregularly truncated, a marginal rimoportula (arrow), and siliceous ridges (small arrows) dividing valve face and mantle. Fig. 16. Another terminal valve showing details of the areolae, siliceous ridges (small arrows) around bases of the TF's, and a marginal rimoportula with slightly inflated tip (arrow). Fig. 17. Details of the three to four satellite pores surrounding each fultoportula (arrows).