Annelida

**Definition:** A phylum of metazoan invertebrates comprising the segmented worms, and including marine annelids (POLYCHAETA), freshwater annelids, earthworms (OLIGOCHAETA), and LEECHES. Only the leeches are of medical interest. (Dorland, 27th ed)

**Tree numbers:** - B01.050.500.091

**Synonyms:** - Segmented Worms - Worms, Segmented