Light (A-C) and scanning electron (D-I) micrographs of Alabasta militaris. (A, B) View of several specimens to illustrate variability in shape and size of the shell. (C-E) Broad lateral view of three individuals to show the general shape. (F) Broad lateral view of apertural region showing strongly curved, fan-shaped aperture. (G) Narrow lateral view of aperture to illustrate its deep lateral notch and thick collar of organic cement. (H, I) Details of shell surface showing different shape and arrangement of shell-plates.