caption: The image shows four different types of freshwater mussels on a black background, with the text "Anodon Pacifica Heude, 1878 USNM 472421" at the top. The mussels are arranged in a symmetrical pattern, with each one having a unique shell shape and texture. The colors of the shells 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.