FIGURES 25–30 in Valve ultrastructure of Nitzschia shanxiensis nom. nov., stat. nov. and N. tabellaria (Bacillariales, Bacillariophyceae), with comments on their systematic position

FIGURES 25–30. SEM micrographs of Nitzschia shanxiensis. 25. External view of the valve, showing the keel extending marginally from apex to apex. 26. Central area showing the raphe is without central raphe ending, areolae are circular to elongate. 27. Valve terminus showing the hooked raphe ends. 28. Internal view of the valve, showing the canal raphe subtended by fibulae. 29. Internal view of valve center showing the fibulae structures. 30. Distal raphe ends showing helictoglossae and are positioned on the mantle at the apices.