Segmentation

In some animals the body is built up out of a series of repeated units, or segments. When the body is divided, both on the outside and on the inside, into such segments, with at least some of the organs repeated in a regular series from one segment to the next, the arrangement is called metameric segmentation, and the phenomenon itself is known as metamerism. The earthworm is the standard example: its body is marked externally into ring-like segments, and this segmentat …