Light (A) and scanning electron (B-I) micrographs of Sphenoderia lenta. (A, B) View of many specimens to illustrate variability in shape and size of the shell. (C) Two individuals at final stage of division. (D) Broad lateral view to illustrate arrangement of shell-plates on the shell surface. (E) Narrow lateral view. (F) Apertural view. (G-H) Close up view of aperture to illustrate shape and arrangement of apertural-plates and structure of the collar. (I) Detail of shell surface to show overlapping shell-plates.