To know more about this synonymy, please read the papers which are cited below.

References

Cori C. J., 1889. Beitrag zur Anatomie der Phoronis. Inaug.-Diss. Prague (Univ. Leipzig), 48 pp.

Roule L., 1889. Sur une nouvelle espèce méditerranéenne du genre Phoronis. C. R. Acad. Sci. Paris, 109, 195-196. (The volume was issued in 1890)

Cori C. J., 1890. Untersuchung über die Anatomie und Histologie der Gattung Phoronis. Z. wiss. Zool., 51, 480-568.

Emig C. C., 1966. Anatomie et écologie de Phoronis psammophila Cori (Golfe de Marseille; Etang de Berre). Rec. Trav. St. mar. Endoume, 40, 161-248.

Febvre J., 1966. Aperçu sur les peuplements benthiques de l'étang de Berre. Rec. Trav. St. mar. Endoume, 41 (57), 123-132.

Febvre J., 1968. Etude bionomique des substrats meubles de l'Etang de Berre. Rec. Trav . Sta. mar. Endoume, 60, 297-355.

Emig C. C., 1969. Considérations sur la systématique des Phoronidiens. III. Phoronis psammophila Cori, 1889, et Phoronis architecta Andrews, 1890. Bull. Mus. Nat. Hist. nat. Paris, 41, 312-327.

Emig C. C., 1971. Taxonomie et systématique des Phoronidiens. Bull. Mus. Nat. Hist. nat. Paris, (Zool.) 8, 469-568.

Roule L., 1900. Sur le développement embryonnaire des Phoronidiens. Ann. Sci. nat., 11, 51-247.

• The first one is related, not to the original description by Andrews (1890), but to the study of Brooks W. K. & R. P. Cowles (1905): for a specialist of the Phoronida, there is no doubt that the characters of two species have been mixed in the description, that are those partly of P. psammophila and of P. muelleri. For example, longitudinal muscles arrangement and nephridia morphology of P. psammophila and non-brooding pattern of P. muelleri. Finally, the clue came in Emig's paper (1977) when these two species were sampled together in the type-locality of P. architecta. Consequently, the previous statements to consider this species as a taxonomic mix (see Emig, 1971, 1973) were corroborated. Nevertheless...

  Recently Santagata & Zimmer (2002)^{a, b, c} are following with this confusion. The point is not to write as did these authors "considering the differences in the reproductive patterns of the adults, the synonymy of Phoronis architecta under Phoronis psammophila cannot be accepted" but, on the basis of phylogenetic characters, to propose morphological character(s) to separate both “species”, nothing about in the paper of Santagata & Zimmer (2002). So until such information will be published, using at least the established phylogenetic characters (Emig, 1985) and a new cladistic analysis, P. architecta should remain a synonym of P. psammophila because the specimens CANNOT be distinguished, simply because belonging to the same species (sse also below point two about the use of the name architecta).
  P. psammophila and P. muelleri have been recorded in many places in the Pacific Ocean (see the geographic distribution for each of those species) and in particular along the East coast of America.

  Now about larvae, there is a point that Santagata & Zimmer (2002), who sampled in California USA (Los Angeles), have missed: the larva is unknown for three species of Phoronida, Phoronis australis, Phoronopsis albomaculata and Phoronopsis californica^a.

  The last point but not the least is related to identification of the specimens in Genbank : what are the taxonomic and phylogenetic characters of the listed specimens ?
  For Phoronida, I agree that it is a bit difficult because histological slides are required to identify adult specimens. Specimens of various species may also be mixed in soft sediments (see example above; others have been published by Emig).

  ^a  One should argue that the recorded phoronid species along the East coast of North and Central America are... all known phoronid species except P. australis ! That are: Phoronis ovalis, P. hippocrepia, P. ijimai, P. muelleri, P. psammophila, P. pallida, Phoronopsis albomaculata, Phoronopsis harmeri, Phoronopsis californica.

  ^b  See also about Phoronis vancouverensis (synonym of P. ijimai)

  ^c  See also about Phoronopsis viridis (synonym of Phoronopsis harmeri)

• The second point is dealing with political systematics. Two countries in the World are rather fun in... the USA and New-Zeland, and scientific arguments are not always the matter !
  New-Zealand is dealing with endemism, a national scientific game ! While the USA seems to be related to the scientific imperialism that means that any US species is a valid species... at least for the Phoronida: Phoronis architecta not P. psammophila, first described in Europe, is not an unique case among the Phoronida, another one is Phoronopsis viridis, a synonym of Phoronopsis harmeri, originally described in Canada. Many other zoological groups show similar cases. This is as old as the Phoronida... nevertheless recent papers testify that such a use is continuing in US papers, without scientific bases (see also Emig 1982, p. 3).

To know more about this synonymy, please read the papers the references of which are cited below.

References

Andrews E. A., 1890. On a new species of the remarkable animal Phoronis. Ann. Mag. nat. Hist., 5, 445-449.

Brooks W. K. & R. P. Cowles, 1905. Phoronis architecta: its life history, anatomy and breeding habits. Mem. Nat. Acad. Sci. Washington, 10 (4), 72-113.

Emig C. C., 1971. Taxonomie et systématique des Phoronidiens. Bull. Mus. Nat. Hist. nat. Paris, (Zool.) 8, 469-568.

Stancyk S. E., F. J. S. Maturo Jr & R. W. Heard Jr, 1976. Phoronids from the East coast of the United States. Bull. mar. Sci., 26 (4), 576-584.

Emig C. C., 1977. Notes sur la localisation, l'écologie et la taxonomie des Phoronidiens. Téthys, 7 (4), 357-364.

Santagata S. & R. L. Zimmer, 2002. Comparison of the neuromuscular systems among actinotroch larvae: systematic and evolutionary implications. Evolution and Development, 4 (1), 43-54.

For know more about those synonymies, please read the papers which are refered below (see also the references on A. sabatieri).

References

Emig C. C., 1982. The biology of Phoronida. Adv. mar. Biol., 19, 1-89.

Roule L., 1900. Sur le développement embryonnaire des Phoronidiens. Ann. Sci. nat., 11, 51-247.

Selys-Longchamps M. de, 1903. Über Phoronis und Actinotrocha bei Helgoland. Wiss. Meeresunters., Helgoland, 6, 1-55.

Selys-Longchamps M. de, 1907. Phoronis. Fauna Flora Neapel, 30, 1-280.

Selys-Longchamps M. de, 1907. Développement post-embryonnaire et affinités des Phoronis. Mem. Sci. Acad. Roy. Belgique, 1, 1-150 (1904).