No list will be completely satisfactory. Authorities differ in what they consider a phylum, and in the actual name of the phylum. The introvert advantage pdf free this, there is agreement on most phyla. These modern techniques have led to changes and renaming of many higher categories.
Despite their rather limited body form, this is a major phylum, with huge numbers in every conceivable habitat. Over 80,000 species have been described, and 15,000 are parasitic. It has been estimated that the total number may be several hundred thousand. They spend their larval stage in the body cavity of arthropods.
The adult stage is free, but non-feeding, though it may live for several months. Priapula: small phylum of 18 species, with large front section which can be drawn back into the body cavity and extruded for feeding. The larger species are carnivores, seizing prey. Only 110 species from two families, they are relatives of the Arthropods. A recent estimate of the number of arthropods on Earth today is 3. There are many opinions about its classification.