Also found in: Dictionary, Encyclopedia, Wikipedia.


A phylum composed of soft-bodied, bilaterally symmetric wormlike marine animals with gill-slits to the pharynx and a conical proboscis; a ciliated larval stage resembles that of echinoderms.
Synonym(s): Hemichorda
[hemi- + Mod. L. chordata, having a notochord, fr. G. chordē, string]
Farlex Partner Medical Dictionary © Farlex 2012
References in periodicals archive ?
Of the four phyla, HcAs in Ctenophora, Porifera, and Hemichordata were reported previously (Aguilera et al., 2013; Martin-Duran et al., 2013).
A taxonomic revision of the family Harrimaniidae (Hemichordata: Enteropneusta) with description of seven species from the Eastern Pacific.
The proteins turned to be few; for example, only one "exclusive" protein was found in each of the Mollusca, Hemichordata, and Echinodermata proteomes.
He said these tubes are the missing link connecting the two main hemichordata groups, which also included the now-extinct graptolites.
It is the basal phylum to Arthropoda, Chordata, Hemichordata, and Echinodermata.
2 and 5 Other Metazoa Phyla Other Eukaryote Phyla Chaetognatha Ciliophora Ctenophora Other Alvelata Entoprocta Amoebozoa Hemichordata Cryptophyta Loricifera Loukozoa Gnathifera Glaucophyta Onochophora Choanozoa Porifera Picozoa Rotifera Foraminifera Xenoturbeiidea Rhodophyta Acanthocephala Myzozoa Chordata Apusozoa Cycliophora Heliozoa Gnathostomulida Percolozoa Kinohycha Euglenozoa Mesozoa Haptophyta Nematomorpha Metamunada Placozoa Cercozoa Priapulida Radiozoa Sipuncula Uncultured unicellular Uncultured Metazoa Eukaryote Acknowledgments
Deep-sea acorn worms (Hemichordata) leave spiral fecal trails on the sea floor while feeding, and these are clockwise or counterclockwise with the head oriented out as in hagfish (Smith et al., 2005; Anderson et al., 2011).
Among them, symbiotic or parasitic copepods constitute about one-third of the known copepods (Ho, 2001), and the hosts include all major groups of marine animals, including Porifera (Bandera et al., 2005), Cnidaria (Humes, 1985b), Mollusca (Huys, 2001), Crustacea (Humes and Ho, 1969), Echinodermata (Boxshall and Ohtsuka, 2001), Urochordata (Ooishi, 2001), Hemichordata (Mayer, 1879; Kesteven, 1913), and Chordata (Abaunza et al., 2001).
Here we present a molecular phylogeny of Hemichordata that includes novel sequence data from 35 taxa representing all hemichordate families, at least 12 of which are distinct genetic lineages not attributable to known species.
The phylum Hemichordata is divided into two classes: Pterobranchia and Enteropneusta.
A parallel situation exists for the phylum Hemichordata, wherein enteropneusts form their coeloms largely by enterocoely, but pterobranchs do so by schizocoely (Lester, 1988); however, an evolutionary explanation of the difference is hampered by current uncertainty as to whether pterobranchs are basal or derived within the phylum (Sato et al., 2008).
Structure, ultrastructure, and function of the preoral heart-kidney of Saccoglossus Kowalevskii (Hemichordata, Enteropneusta) including new data on the stomochord.