Light (A) and scanning electron (B-I) micrographs of Phryganella acropodia. (A, B) View of many specimens to illustrate variability in shape and size of the shell. (C-D) Apertural view of two specimens showing general shape. (E) Lateral view. (F) Dorsal view. (G) Close up view of aperture to illustrate its smooth rim and circular outline. (H, I) Details of lateral and dorsal side of the shell to illustrate its rough surface, covered with large pieces of quartz.