Fig. 2. SEM. Right valve. Cell broadly heart-shaped with rounded posterior. Periflagellar area barely visible.
Fig. 3. SEM. Left valve. Valves asymmetrical.
Fig. 4. SEM. Areolae ovoid, oblong or circular. Many with small central pores (arrows).
Fig. 5. SEM. Sieve-like depression deep and ovoid; perforated with numerous small pores.
Fig. 6. SEM. Intercalary band transversely striated. Round porous (sieve-like) depression (arrowhead), along posterior margin, separated from intercalary band by row of areolae.
Fig. 7. SEM. Apical view. Periflagellar area set between left and right valves in shallow raised depression surrounded by thickened apical ridge. Ovoid flagellar pore adjacent to oblong auxiliary pore. A=auxiliary pore; F=flagellar pore.