P Levanderi Guide
Credit: Marina Potapova
  1. Valves elliptic to linear-elliptic
  2. Raphe valve with small, asymmetric central area
  3. Rapheless valve with rhomboid axial area

Valves are elliptical to linear-elliptic. The raphe valve has a linear axial area and a small asymmetric central area. The rapheless valve has a rhomboid axial area, which often has an irregular border. The central area on rapheless valve is usually not differentiated from the axial area. Striae are slightly radiate in the center and strongly radiate at the apices of both valves, 25-31 in 10 ┬Ám. Areolae are often visible in LM.