Hydrotheca campanulate, 350-740 [micro]m (n = 10) deep from rim to base, 215-340 [micro]m (n = 10) wide at margin, 100-180 [micro]m (n = 10) wide at diaphragm; diaphragm thin, transversal; operculum with 8-11 triangular to pentagonal valves (n = 10), apparently as folded continuation of hydrothecal wall, but with discrete line demarcating operculum from hydrotheca (only in SEM).
gracilis revealed the presence of a tenuous line separating the operculum from the hydrotheca (Fig.