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About Polychaetes
Worms that are not polychaetes

Chaetognatha  -  arrow worms


Chaetognatha [illustrator: Damon Kowarsky]

Chaetognaths are narrow-bodied and often transparent, with paired lateral fins and a tail fin and distinctive grasping spines at the mouth. They are unsegmented.


Chaetognaths are readily recognised from the distinctive grasping spines, used to catch planktonic prey, and the paired lateral fins giving rise to the common name arrow worms. They appear superficially fish-like but are apparently not closely related to chordates. Most chaetognaths are planktonic and although they are common enough in benthic samples this almost certainly occurs due to contamination of the sample with planktonic organisms from unfiltered deck hoses. However, members of the genus Spadella are benthic and occur in shallow water in southern Australia.


Bieri, R. 1989. Khohnittellidae and Bathybelidae, new families in the Phylum Chaetognatha; the rejection of the family Tokiokaispadellidae and the genera Tokiokaispadella, Zahonya, and Aberrospadella. Proceedings of the Biological Society of Washington 102, 973-976.

Edgar, GJ. 2000. Australian Marine Life. Reed, Kew, Victoria.

Johnston, TH and Taylor, BB. 1919. Notes on Australian Chaetognatha. Proceedings of the Royal Society of Queensland 31, 28-41.

Lutschinger, S. 1993. The Marine Fauna of New Zealand: Chaetognatha (Arrow Worms). New Zealand Oceanographic Institute Memoirs 101, 1-61.

O'Sullivan, D and Hosie, G. 1985. A general guide to the metazoan zooplankton groups of the Southern Ocean. Australian National Antarctic Research Expeditions Research Notes 30, 1-59.

Thomson, JM. 1947. The Chaetognaths of south-eastern Australia. Council for Scientific and Industrial Research Bulletin, Australia 222, 1-43.