upper lens eye

Ernst Haeckel's Kunstformen der Natur (Artforms of Nature) was a landmark in biological illustration. Published in 1904, it was lavishly illustrated with 100 exquisitely detailed lithographic plates, including this one, showing nine different species of cubomedusae, or box jellyfish. It has been known, since around the time that Haeckel's masterpiece was published, that box jellyfish have a unique visual system which is more sophisticated than that of other jellyfish species. They boast an impressive set of 24 eyes of four different types, which are clustered within bizarre sensory appendages…