Placoneis Gastrum Guide
Credit: James Woodell
  1. Valves elliptic
  2. Apices broadly rounded to rostrate
  3. Striae strongly radiate
  4. Areolae punctate
  5. Central area variable

Valves are elliptic, with broadly rounded to rostrate apices. Striae are strongly radiate and composed of punctate, uniseriate areolae. The central area is variable in shape - transverse to elliptic to irregular. The proximal raphe ends are expanded.