Light (A, C) and scanning electron (B, D-I) micrographs of Heleopera rosea. (A, B) View of many specimens to illustrate variability in shape and size of the shell. (C) View of encysted specimen. (D, E) Broad lateral view of two specimens showing variability of shell structure. (F) Apertural view to show a narrow, closed aperture of encysted specimen. (G) Broad lateral view of aperture showing the bordering thin band of organic cement. (H) Portion of anterior part of the shell to show its smooth surface, composed of siliceous shell-plates. (I) Portion of posterior part of the shell to show its rough surface, covered mainly by flattish quartz particles.