The Phoronida is an exclusively marine group of lophophorate animals: infaunal, suspension-feeders, with a vermiform body enclosed in a slender, chitinous tube in which it moves freely and it is anchored by the ampulla, the end-bulb of the body. The tube is embedded in hard or soft substrates.
 

Currently the PHORONIDA are constituted by only two genera, without any intermediate hierarchical level, and a "generic" technical name for the larvae (see Emig, 1971, 1979, 1982). However, following a “technical” request of Nielsen (2013) at the International Commission of Zoological Nomenclature (ICZN), Phoronida is seen granting a hierarchy without any diagnosis and any historical study on the systematics of this group: "7. Phoronis is the base for the names of the family PHORONIDAE, the order, class and phylum Phoronidea/Phoronida, in principle all dating from Hatschek (1888, p. 40), who introduced Phoronida as a class name."

• Phoronis, Wright, 1856, without epidermal invagination at the base of the lophophore. This genus is recognised with eight species. The name Phoronis, given by Wright (1856) for the genus name and stated by him, is one of the numerous epithets of the Egyptian goddess Isis.
  Genera synonymouss : Crepina Van Beneden, 1858 ; Phoronella Häckel, 1896.


• Phoronopsis, Gilchrist, 1907, has an epidermal invagination at the base of the lophophore, and three well-defined species.


• Actinotrocha : The larva of the Phoronids, named actinotroch, keeps a separate "generic" name considered as a technical term under Actinotrocha which has sometimes still a name different from the adult species name, name of the author and date of description must be added.
  To be read : or - Some systematicians, even members of the International Commission on Zoological Nomenclature, unaware of the rules used for in phoronid taxonomy, would basically apply the Code contrary to its own rules. First of all, before getting a peremptory opinion, this Code-fundamentalists should learn the history of the Phoronida and read the publications about of the specialists who have worked on over 150 years.
  
  In answer at the request of Nielsen (2013) - see above- the larvae of Phoronida keep their name but without author's name, nor date. Nevertheless, following a tradition more than 150 years old, followed by all the specialists of the Phoronida, and as my mentor Lars Silén proposed in 1952, I will keep the name followed by the author and the year.

Phoronids are found in all oceans and seas (except the Antarctic) and are not uncommon in favourable situations. In some habitats they are very abundant, reaching several tens of thousand individuals per square metre.
Phoronids occur at depths ranging from the intertidal zone to about 400 m depth, but mainly between 0 to 70 m.
Almost all species have wide geographical ranges and most are probably cosmopolitan.