Guide to Surirella striatula
Credit: Peter Fedrigon
- Valves large, elliptic, twisted
- Porcae undulate
- Axial area ridge-like
- Triangular area at apex
Valves are large and elliptic, often twisted and slightly heteropolar. Distinct porcae, or ribs, are undulate and radiate throughout the valve. The axial area is ridge-like and branches to the valve margin. A triangular shaped area is present at one, or both, apices.