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n. pl.1.(Zool.) A group of wormlike invertebrates having, along the sides of the body, branchial openings for the branchial sacs, which are formed by diverticula of the alimentary canal. Balanoglossus is the only known genus. See Illustration in Appendix.
References in periodicals archive ?
At present, 135 hemichordate species are described: 121 are solitary Enteropneusta, or acorn worms; and 24 are colonial, tube-dwelling Ptero-branchia (Appeltans et al.
The phylum Hemichordata is divided into two classes: Pterobranchia and Enteropneusta.
The deuterostome phylum Hemichordata is composed of three extant classes: the Enteropneusta are solitary worms, the Pterobranchia are colonial tube-dwelling suspension feeders, and the Planktosphaeroidea are known only from their larvae.