Annelida

Century Dictionary and Cyclopedia

1. The annelids or Annelides, a class of invertebrate animals, of the phylum Vermes, sometimes called the class of red-blooded worms. The body is composed of numerous (up to some 400) segments, somites, or metameres, and limbs are wanting, or, if present, are rudimentary and consist of the cilia or setæ known as parapodia. A vascular system with red blood is usually present; the integument is soft, and composed of many layers, the surface being mostly ciliate or setose; the head is wanting or rudimentary, and in the latter case consists of a prostomium which may be cirriferous or tentaculiferous. The Annelida are the “worms,” properly so called, of which the common earthworm, lobworm, and leech are characteristic examples. Most of the species are aquatic and marine. The class is differently limited by different authors, the principal variation among later writers, however, being in excluding or including the Gephyrea. Excluding these, as is done by the above definition, the Annelida have been divided into four orders: Hirudinea, Discophora, or Suctoria, the leeches;
2. In Huxley's system (1877), a superordinal division including the Polychœta, Oligochœta, Hirudinea, and Gephyrea, with the Myzostomata doubtfully added thereto: a group the members of which resemble one another generally in the segmentation of the body indicated at least by the serially multiganglionate nervous centers (wanting in most Gephyrea), in the presence of cilia and segmental organs, and in the nature of the larvæ, which are set free when the embryos hatch.

Wiktionary

1. n. A taxonomic phylum within the superphylum Protostomia — the annelid worms.

GNU Webster's 1913

1. n. (Zoöl.) A division of the Articulata, having the body formed of numerous rings or annular segments, and without jointed legs. The principal subdivisions are the Chætopoda, including the Oligochæta or earthworms and Polychæta or marine worms; and the Hirudinea or leeches. See chætopoda.

WordNet 3.0

1. n. segmented worms: earthworms; lugworms; leeches.