Worms

The term worm /ˈwɜrm/ refers to an obsolete taxon (vermes) formerly used for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly related animals that typically have a long cylindrical tube-like body and no legs. Most animals called "worms" are invertebrates, but the term is also used for the amphibian caecilians and the slow worm Anguis, a legless burrowing lizard. Invertebrate animals commonly called "worms" include annelids (earthworms), nematodes (roundworms), platyhelminthes (flatworms), marine polychaete worms (bristle worms), marine nemertean worms ("bootlace worms"), marine Chaetognatha (arrow worms), priapulid worms, and insect larvae such as caterpillars, grubs, and maggots.

Various types of worm occupy a small variety of parasitic niches, living inside the bodies of other animals. Free-living worm species may live on land, in marine or freshwater environments, or burrow.