Acorn worms

class of hemichordates

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.

Saccoglossus is a genus of acorn worm. It is the largest genus in the Enteropneusta class, with 20 species.

Ptychoderidae is a family of acorn worms.

Harrimaniidae is a basal family of acorn worms. A taxonomic revision was undertaken in 2010, and a number of new genera and species found in the Eastern Pacific were described. In this family the development is direct without tornaria larva, and circular muscle fibers in their trunk is missing. There is some indication that Stereobalanus may be a separate basal acorn worm lineage, sister to all remaining acorn worms.

Spengelidae is a family of worms belonging to the class Enteropneusta, order unknown. The larvae of one of its species, Schizocardium californicum, are known for not expressing Hox genes.

Harrimania is a genus of acorn worms belonging to the family Harrimaniidae.

Stereobalanus is a genus of acorn worms belonging to the family Harrimaniidae.

Torquaratoridae (Latin for "neck plow") is a family of acorn worms (Hemichordata) that lives in deep waters between 350 and 4000 meters. They can grow up to 1 m (3 ft) in length and have semitransparent gelatinous bodies, often brightly colored.

Ptychodera is a genus of acorn worm.

species of hemichordates

Glossobalanus is a genus of worms belonging to the family Ptychoderidae.

species of Enteropneusta

species of hemichordates

species of hemichordates

Mesoglossus is a genus of worms belonging to the family Harrimaniidae.

species of hemichordates

species of hemichordates

species of hemichordates