FIGURES 11–16 in Entogoniopsis gen. nov. and Trilamina gen. nov. (Bacillariophyta): a survey of multipolar pseudocellate diatoms with internal costae, including comments on the genus Sheshukovia Gleser

FIGURES 11–16. Scanning electron micrographs of Entogoniopsis morlandii from Oamaru, New Zealand (Figs 11, 13, 15–16), and Vema Cruise 17, Core 107, South Atlantic Ocean (Figs 12, 14). Fig. 11: Oblique external view, showing a depressed valve face surrounded by a hyaline marginal ridge level with the summits of the polar pseudocelli. Central ring of rimoportulae indicated by arrowhead. Areas of sparse, scattered areolation next to the proximal sides of polar elevations are indicated with arrows. Fig. 12: Oblique internal view showing the prominent internal costae. Central ring of rimoportulae indicated by arrowhead. Fig. 13: Detail of the specimen in Fig. 11, showing fractured buttressed external tubes of the rimoportulae, and partially dissolved volae. Fig. 14: Detail of the specimen in Fig. 12, showing an irregular central ring of rimoportulae, internal openings in the form of slightly raised slits. Fig. 15: Detail of the specimen in Fig. 11, showing one of the polar pseudocelli. Note the flat summit occupying the whole of the pseudocellus located on the valve face. Fig. 16: Detail of a fractured valve revealing a T-shaped cross-section through a costa (arrowhead), and an inward expansion of the hyaline mantle margin (arrow).