Widespread and large group of animals (more than one million of species: Jointed worms, spiders, woodlouses, crabs, insects).

The articulates are by far the largest group of animals. The organisms are constructed of subsequent, homologous segments. In the case of insects, e.g., one segment is forming the head, three segments are forming the chest and eleven segments are forming the abdomen. Most higher forms of the articulates are characterized by an exoskeleton containing chitin.