caption: The image shows a group of four oysters on a black background with the text "Unio Johannis Lea, 1859, Holotype USNM 84830" written on them. The oysters are arranged in a triangular formation, with the largest oyster in the center and two smaller oysters surrounding it. The shells are a light brown color with a glossy sheen, and the text is written in a bold white font.