Light (A) and scanning electron (B-I) micrographs of Quadrulella variabilis. (A, B) View of many specimens to illustrate variability in shape and size of the shell. (C, D) Broad lateral view of two specimens to show the general shape. (E) Latero-apertural view. (F) Narrow lateral view. (G) Lateral view of aperture. (H) Close up view of aperture to illustrate its elliptical shape and bordering thin collar of organic cement (I) Detail of shell surface showing shape and arrangement of shell-plates.