

This is one of the plates from the 100 illustrations in Kunst-Formen der Natur, or “Art Forms in Nature,” by Ernst Haeckel, a scientist – or philosopher of science – who gave us the idea “ontogeny recapitulates phylogeny.” That means that as a creature develops before it’s born, the stages it goes through resemble or re-enact the process of its evolution. Little embryonic humans grow gills and tails before shaping up into something like a recognizable baby. He wrote books with names like The Riddle of the Universe and The History of Creation, Or, The Development of the Earth and Its Inhabitants by the Action of Natural Causes: A Popular Exposition of the Doctrine of Evolution in General, and of that of Darwin, Goethe, and Lamarck in Particular.
But he also produced this pretty incredible collection of organic geometry in 1899 – page after page of carefully arranged coral polyps, or squids, or flowering trees, or single-celled organisms like diatoms.
The Cystoidea are a class of prehistoric echinoderms, which means they were relatives of sea urchins and sand dollars: the critters that are like jellyfish with armor, and maybe a few more internal organs.
H.P. Lovecraft took some inspiration from here, which you can definitely see if you’ve every gotten into his stories of supra-dimensional entities with stalks, tentacles, and inhuman geometries.