arrow worm

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Related to arrow worms: acorn worms

arrow worm

n.
Any of various small slender marine worms of the phylum Chaetognatha, having a narrow, almost transparent body and spines on each side of the mouth that are used for grasping prey. Also called chaetognath.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Translations
nuolimato
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References in periodicals archive ?
They debated for decades over whether to group Amiskwia under arrow worms, ribbon worms or a separate family altogether. 
Vinther explained that the discovery of Amiskwia having a body similar to an arrow worm and jaws like a gnathiferan led researchers to believe that arrow worms and gnathiferans are more closely related than previously believed.
The study's lead author Jakob Vinther, a senior lecturer with the School of Earth Sciences at the University of Bristol in the United Kingdom, told (https://www.livescience.com/64857-ancient-worm-hidden-jaws.html) Live Science that while Amiskwia has a resemblance to its cousins in the arrow worm family, it didn't actually have their distinctive structures, such as spines near the head that are used for catching and holding on to prey.
Some examples include arrow worms (or chaetognaths - see photo above) and amphipods (photo at right), which are voracious predators on copepods and larvae of larger species.
Haddock and Case (1994) reported the first known species of bioluminescent arrow worm, Caecosagitta macrocephala (Fowler, 1904), a deep-living species usually found at depths greater than 700 m.
Both of the luminescent species of arrow worm, despite coming from widely separated orders within the phylum, share the relatively uncommon trait among chaetognaths of having an orange-pigmented gut lining (Terazaki et al., 1977).
Oriented light reactions of the arrow worm Sagitta crassa Tokioka.