Introduction to the Annelida Everybody's favorite, worms. . . Segmented worms make up the Phylum Annelida. The phylum includes earthworms and their relatives, leeches, and a large number of mostly marine worms known as polychaetes. Various species of polychaete are known as lugworms, clam worms, bristleworms, fire worms, sea mice, and EWWW! I stepped on that THING! Annelids can be told by their ...