collagenous tubular structure called a coenecium. The body plan of hemichordates is characterized by a muscular organization. The anteroposterior axis...

found in all chordates, including tunicates (in the larval stage). Some hemichordates also have a tubular nerve cord. In the early embryonic stage, it looks...

fourth chordate subphylum, but now is treated as a separate phylum. Hemichordates are now thought to be closer to the Echinoderms, and together they form...

or Enteropneusta are a hemichordate class of invertebrates consisting of one order of the same name. The closest non-hemichordate relatives of the Enteropneusta...

repeated segments are controlled by similar developmental mechanisms. Some hemichordate species can have as many as 200 gill slits. Pharyngeal clefts resembling...

to be related to the hydrozoans; now they are widely recognized as hemichordates. The name "graptolite" originates from the genus Graptolithus ("writing...

of pterobranch hemichordates: history and perspectives". Genesis. 46 (11): 587–91. doi:10.1002/dvg.20395. PMID 18798243. Hemichordate Nervous System Loduca...

  Echinoderms, hemichordates, cephalochordates, urochordates   Vertebrates...

and nematodes; and the deuterostomes, which include the echinoderms, hemichordates and chordates, the latter of which contains the vertebrates. The simple...

animal phyla (including arthropods, molluscs, annelids, echinoderms, hemichordates and chordates) appear. Reef-building archaeocyathan sponges initially...