The Platyzoa are a group of Phyla Mollusca Arthropoda Annelida Protostomes (from the Greek: first the mouth) are a superphylum of animals in the taxonomic group bilateria, and include animals such as arthropods, mollusks, and nematodes. They are most often compared with deuterostomes, the other major group of bilateria. The major distinctions between deuterostomes and protostomes... protostome animals. They include the Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. With about 20,000 species they are largest phylum of Acoelomates. Flatworms are found in marine, freshwater, and even damp terrestrial environments. Most are free-living forms... Platyhelminthes or flatworms, together with several exclusively microscopic phyla:

• Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. With about 20,000 species they are largest phylum of Acoelomates. Flatworms are found in marine, freshwater, and even damp terrestrial environments. Most are free-living forms... Platyhelminthes
• The gastrotrichs are a phylum of microscopic animals, found in fresh water and marine environments. They are bilaterally symmetric, with a complete gut. The body is covered with cilia, especially about the mouth, and has two terminal projections that serve as adhesive tubes. Like many microscopic animals, their locomotion is... Gastrotricha
• Classes Seisonoidea Bdelloidea Monogononta The rotifers make up a phylum of microscopic, pseudocoelomate animals. Most rotifers are around 0.1-0.5 mm long, and are common in freshwater throughout the world with a few saltwater species. Rotifers get their name (derived from Latin and meaning wheel-bearer; they have... Rotifera
• Classes Archiacanthocephala Palaeacanthocephala Eoacanthocephala The Acanthocephala (gr. Acanthus - thorn Kephale - head)is a phylum of parasitic worms, characterised by the presence of an evertable proboscis, armed with spines, which it uses to pierce and hold the gut wall of their host. Acanthocephalans typically have complex life cycles, involving a number... Acanthocephala
• Gnathostomulids, or jaw worms, are a small phylum of microscopic marine animals. They appear closely related to rotifers and their allies, together making up the Gnathifera. Gnathostomulids have no fossil record. Categories: Animal stubs | Animals ... Gnathostomulida
• Binomial name Limnognathia maerski Kristensen & Funch, 2000 Limnognathia maerski is a microscopic animal, discovered in Greenland in 2000, that is given its own phylum, Micrognathozoa. It is related to the rotifers and gnathostomulids, grouped together as the Gnathifera. Categories: Stub | Animals ... Micrognathozoa

The Binomial name Symbion pandora Funch & Kristensen, 1995 Symbion is a genus of peculiar animals, with a single species, S. pandora. It was discovered in 1995 by Reinhardt Kristensen and Peter Funch on the mouthparts of the Norwegian lobster Nephrops norvegicus. Symbion does not appear to have any especially close... Cycliophora may also belong here. The Platyhelminthes and Gastrotricha are acoelomate. The other phyla have pseudocoeloms, and share characteristics such as the structure of their jaws and pharynx, although these have been secondarily lost in the parasitic Acanthocephala. They form a monophyletic subgroup called the Gnathifera.

The Platyzoa are close relatives of the The Lophotrochozoa or Spiralia are one of three major divisions of bilaterian animals, together with the Ecdysozoa and Deuterostomia. They typically include the following phyla: Mollusca Annelida Sipuncula Nemertea Brachiopoda Phoronida Ectoprocta Entoprocta The first four phyla are called the Trochozoa, named for the common presence of trochophore larvae. The... Lophotrochozoa, and are sometimes included in that group. Together the two make up the Spiralia.