Centipedes and millipedes (Subphylum: Miriapoda) are small arthropods (Phylum:Arthropoda) distinguished by having more than four pairs of legs. Their body is divided into two regions: head and trunk. On the head are found the eyes and a pair of short antennae while many pairs of legs (also called appendages). Their name comes from the Greek myria, ten thousand, and podos, feet. Although the popular belief is that millipedes have a thousand legs, the reality is that none have that many. One species which comes close is the millipede Illacme plenipes from California with 375 pairs of legs. The majority of the miriapods are small, of only a few centimeters in length, but there are also giant tropical species that reach lengths of up to 30 cm.
As well as the centipedes (Class: Chilopoda) and millipedes (Class: Diplopoda), the miriapods also include the symphylans or garden centipedes (Class: Symphyla) and pauropods (Class: Pauropoda), microscopic organisms, blind and with frail bodies which, while universally distributed, are uncommon in moist soil and rotting vegetation. Centipedes and millipedes live among the leaf litter or under tree bark and rocks. They are plentiful in the ecosystems, including the tundra.