annelida
The phylum Annelida is made up of segmented worms such as earthworms . Segmented worms are divided into many repeating segments. There are roughly 15,000 species of annelids. Most belong to one of three classes. A species in each class is pictured in Figure below . See The Cambrian Explosion at http://www. pbs. org/kcet/shapeoflife/episodes/explosion. html for an introduction to annelids.