Costa

Rhopalodia Guide  Lm
Image Credit: Ditmar Metzeltin, Marina Potapova, Pat Kociolek
Light micrograph of ventral side of a frustule of Rhopalodia. The costae appear as dark bands parallel to the striae.
Rhopalodia Guide  Sem No Arrow
Image Credit: Ditmar Metzeltin, Marina Potapova, Pat Kociolek
Scanning electron micrograph of ventral side of a frustule of Rhopalodia. The costae appear as ridges on the valve surface.