caption: The image shows three different types of oysters on a black background, with the text "Unio Fibrosus Heude, 1877 USNM 126460" at the top. The oysters are arranged in a symmetrical pattern, with each one having a unique shape and texture. The colors of the oysters range from light to dark, with some having a glossy sheen and others having a matte finish. The text is written in a bold, white font, making it stand out against the dark background.