Elongated oval, wider at posterior end, compressed, umbones near (but not at) anterior end, fragile, translucent shiny ivory white, posterior half with cobwebby streaks, smooth; interior with exterior coloration showing through, umbo reinforced by small smooth rib, margin smooth. Florida, West Indies, Gulf of Mexico, South America (to Uruguay). Length 10 mm (to 21 mm). Compare other Amygdalum species, which lack the cobwebby radial color pattern.