Up to now, less familiar and more diverse animals without backbones (invertebrates) were less carefully considered. Linnaeus had lumped them all into the class Vermes (Latin for 'worms"). Lamarck divided the invertebrates into groups like the crustaceans, echinoderms, and distinguished between the eight-legged arachnids and the six-legged insects.
A visual chronology of Asimov's ~1500 scientific inventions and discoveries.
