WormA worm is any of numerous relatively small elongated soft-bodied invertebrate animals. The most famous is the earthworm, a member of phylum Annelida, but there are hundreds of thousands of different species that live in a wide variety of habitats other than soil. Originally, the word referred to any creeping or a crawling animal of any kind or size, such as a serpent, caterpillar, snail, or the like. Later this definition was narrowed to the modern definition which still includes several different animal groups. Major phyla include: * Annelida (segmented worms) * Sipuncula (peanut worms) * Onychophora (velvet worms) * Acanthocephala (spiny-headed worms) * Nematoda (roundworms) * Nematomorpha (horsehair worms) * Nemertea (ribbonworms) * Platyhelminthes (flatworms) * Gnathostomulida (jaw worms) * Chaetognatha (arrow worms) Some other invertebrate groups may be considered worms. Also, many insect larvae are known as worms, though they are not in a technical sense. It is important also to mention biopsychic variations of this animal, such as Scalpworms, which are a dangerously underdiagnosed condition in adult humans.