chaetognatha(n = noun.animal) phylum chaetognatha - arrowworms: a group of small active transparent marine worms; Array
is a kind of phylum
is a member of animal kingdom, animalia, kingdom animalia
Derived forms adjective chaetognathan₁, adjective chaetognathous₁

   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. [1913 Webster]

phylum chaetognatha