Light (A, C) and scanning electron (B, D-I) micrographs of Argynnia vitraea. (A, B) View of many specimens to illustrate variability in shape and size of the shell. (C, D) Broad lateral view. (E) Apertural view. (F) Narrow lateral view. (G) Close up view of aperture showing its oval and irregularly dentate outline. (H) Detail of shell surface showing shape and arrangement of shell-plates, and porous structure of the organic cement. (I) Close up view of porous organic cement.