Career
He taught at Jena, where he translated Georges Cuvier"s Le Règne Animal (1817), and was the director of the Jena Botanical Gardens (from 1807 to 1850) and the Museum of Zoology. He proposed a classification of the animal kingdom with nine classes, based on body structure, such as those that are soft and gelatinous, those that are articulated and have an exoskeleton, and those that have an endoskeleton.