Credit: Ernst Haeckel
The 99th plate illustration from Ernst Haeckel's Kunstformen der Natur (1904), showing a variety of hummingbirds.Kunstformen der Natur (Art Forms of Nature) is a book of lithographic and autotype prints by German biologist Ernst Haeckel. Originally published in sets of ten between 1899 and 1904 and as a complete volume in 1904, it consists of 100 prints of various organisms, many of which were first described by Haeckel himself.