Millipedes are a diverse group of animals and are not well studied in Australia and of the 15 orders of millipedes in the world only 9 have been recorded in Australia. Millipede means 'thousand feet' but they do not really have this many, although most have over 30 pairs of legs and some are known to have about 350 pairs. Millipedes can be distinguished from other invertebrates by the following characters:
2 pairs of legs per body segment, although some juveniles may posses only 1 pair per segment
Simple eyes if present, although many have no eyes
1 pair of antennae
Although it looks like millipedes have 2 pair of legs on each segment, closer examination shows that each body segment is actually 2 segments fused together. Millipedes are timid invertebrates and unlike centipedes, do not have poisonous claws so to protect themselves and to discourage predators they roll into a tight spiral and often discharge a foul smelling, distasteful substance.
The introduced species Ommatoiulus moreletii (Black Portuguese millipede), often reaches plague proportions in southern Australia invading houses and destroying crops. Numbers can be so great in places that the ground appears a wriggling mass of black millipedes.