Ernst Haeckel's Radiolarians and Medusa: The influence of his visits to Villefranche on his science and his art

International audienceABTRACT: Early in his long career, Ernst Haeckel (1834-1919) twice visited Villefranche-sur-Mer. First, as a student, in 1856 during a sampling trip to Nice, and again in 1864 when sent to Nice by his parents for a change of scenery following the untimely death of his first wife. The two visits appear to have been key events in the development of Haeckel's science and art as they are the beginnings of his studies, first on radiolarians, and then on medusa. During the 1856 visit he observed for the first time living radiolarians, the group of microscopic planktonic protists, the subject of his first monographic work in 1862 that brought him fame at a young age. During the 1864 visit he resided in Villefranche-sur-Mer. There, for the first time, he made detailed observations on the development and morphology of medusa. He subsequently produced monumental monographs on both radiolaria and medusa, e.g., the Challenger Reports, which remain today his major scientific contributions. Haeckel's artistic fame is largely from his Kunstformen der Natur. The book relies heavily on illustrations of both radiolarians and medusa, more so than other groups of organisms, and contains iconic images of medusa and radiolarians, suggesting a major importance in Haeckel's art for the two groups linked closely with Haeckel's visits to Villefranche-sur-Mer