tornaria
{{Short description|Type of planktonic larva}}
A tornaria is the planktonic larva of some species of Hemichordata such as the acorn worms.{{cite web |url=http://www.merriam-webster.com/dictionary/tornaria |title=tornaria |year=2015 |work=Merriam-Webster |accessdate=9 July 2016}} It is very similar in appearance to the bipinnaria larvae of starfishes, with convoluted bands of cilia running around the body.{{cite journal|author1=Nakajima Y|author2=Humphreys T|author3=Kaneko H|author4=Tagawa K.|title=Development and neural organization of the tornaria larva of the Hawaiian hemichordate, Ptychodera flava|journal=Zoological Science|date=January 2004|volume=21|issue=1|pages=69–78|pmid=14745106|doi=10.2108/0289-0003(2004)21[69:DANOOT]2.0.CO;2|doi-access=free}}
It is an oval shaped, transparent larva. The diameter of the body is about 3 mm. It has an apical plate, which is a thickened region provided by a tuft of cilia and a pair of eye spots. The larva has a complete alimentary canal. The ciliary band stretches throughout the anterior and posterior region, and also the postoral region.