Myriapoda, a class of animals belonging to the phylum Arthropoda (q.v.). The members of this group each consist of a head followed by a considerable number of somites, or segments, which are all similar to one another. Each of these has one or two pairs of jointed legs, the former being the case in the centipedes, and the latter in the millepedes. The head is armed with three pairs of appendages: the antennae or feelers, and two pairs of jaws, known as mandibles and maxillae. The myriapods all live on land, and breathe by air-tubes or "tracheae" running throughout the body. The millepedes are vegetarian, and the centipedes carnivorous. The class is divided into two orders, the Diplopoda or Chilognatha, including the millepedes (q.v.), and the Chilopoda or centipedes (q.v.). The remarkable genus Peripatus was once included here, but is now relegated to a, separate class, the Protracheata (q.v.).