Adjacent valves connect through two protuberances. Valves have small windows, contain a single chloroplast, and form straight chains. Each valve has two protuberances near the ends. Thin, perpendicular setae and undifferentiated terminal setae emerge. Setae are circular with a spiral spines and poroid pattern. Primary valve is dome-shaped; secondary valve has conical spines and silica flaps, found only at chain terminals.