Definition of annelida :
A division of the Articulata, having the body formed of numerous rings or annular segments, and without jointed legs. The principal subdivisions are the Chaetopoda, including the Oligochaeta or earthworms and Polychaeta or marine worms; and the Hirudinea or leeches. See Chaetopoda.
- But A soon broke up into two principal stirpes, of which one, a, became the root of the Annelida, Echinodermata, and Arthropoda, while the other, b, gave rise to the Polyzoa and Ascidioida, and produced the two remaining stirpes of the Vertebrata and the Mollusca. - "Critiques and Addresses", Thomas Henry Huxley.