Balanoglossus

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Balanoglossus" – news · newspapers · books · scholar · JSTOR (March 2022) (Learn how and when to remove this message)

Balanoglossus
Unidentified specimen from Réunion
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Hemichordata
Class:	Enteropneusta
Order:	Enteropneusta
Family:	Ptychoderidae
Genus:	Balanoglossus Delle Chiaje, 1829
Species
See text.

Balanoglossus is a genus of ocean-dwelling acorn worms. It has zoological importance because, being hemichordates, they are an "evolutionary link" between invertebrates and vertebrates. Balanoglossus specimens are deuterostomes, and resemble the chordates in that they possess branchial openings.^[1]

Their heads are between 2.5 mm (1/10 in) and 5 mm (1/5 in) wide.