(Gr. for "many-legged"), arthropod animals of which centipedes and millipedes are familiar examples. Linnaeus included them in his Insecta Aptera together with Crustacea and Arachnida; in 1796 P. A. Latreille designated them as Myriopoda, making of them, along with the Crustacean Oniscus, one of the seven orders into which he divided the Aptera of Linnaeus. Later on J. C. Savigny, by study of the mouth-parts, clearly distinguished them from Insects and Crustacea. In 1814 W. E. Leach defined them and divided them into Centipedes and Millipedes. In 1825 Latreille carried further the observations of Leach, and suggested that the two groups were very distinct, the millipedes being nearer Crustacea and the centipedes approaching Arachnida and Insecta. Although Latreille's suggestion has not been adopted, it is recognized that centipedes and millipedes are too far apart to be united as Myriapoda, and they are now treated as separate classes of the Arthropoda. See Centipede (Chilopoda) and Millipede (Diplopoda).