from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. A taxonomic phylum within the superphylum Protostomia — the arrow worms or chaetognaths.
from the GNU version of the Collaborative International Dictionary of English
- n.pl. a phylum consisting of the arrowworms, a group of small active transparent free-swimming marine worms, of which the genus Sagitta is the type. They have groups of curved spines on each side of the head.
from The Century Dictionary and Cyclopedia
- A group of transparent animals consisting of the family Sagittidæ, the affinities of which are still undetermined.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. arrowworms: a group of small active transparent marine worms
Zooplankton composition shows a high abundance of Calanoid Copepoda, Chaetognatha, Salpidae and Hydromedusae.
Of the phyla you haven't seen alive, I have seen: Chaetognatha, Nematomorpha, Nemertea, Sipuncula, Echiura which is really a subgroup of Annelida, Phoronida and Brachiopoda.
The number of species in the upper 200 meters (m) of the pelagic oceanic environment is well known for four groups of animals, the Euphausicacea, Chaetognatha, Pteropoda and Copepoda, which dominate the biomass everywhere.
Arrow worms (Phylum Chaetognatha) are abundant planktonic organisms and important predators in many food webs; yet, the classification and evolutionary relationships among chaetognath species remain poorly understood.
Instead, I will list a compilation of some of the phyla of which I have yet to see a live member: Acanthocephala, Chaetognatha, Gnathostomulida,
Barcoding of Arrow Worms (Phylum Chaetognatha) from Three Oceans: Genetic Diversity and Evolution within an Enigmatic Phylum