Caloneis Silicula Guide
Credit: Pat Kociolek
  1. Valves biconstricted
  2. Lunate thickenings near central area
  3. Longitudinal line present

Valves linear and biconstricted. The axial area is narrow, broadening to a transverse fascia with lunate thickenings on either side of the central area. A fine longitudinal line is present near the valve margins.