Chaetognatha A phylum that comprises the ‘arrow worms’, first encountered in the fossil record in Carboniferous rocks. They are characterized by the possession of horizontal fins that flank the trunk and tail. The body is semi-transparent, streamlined, and divided into a head, trunk, and post-anal tail region. The head bears eyes and food-catching spines. Arrow worms are common among marine plankton.

Chaetognatha A phylum of marine coelomate invertebrates, the arrow worms, in which the head bears hooks for catching prey and the trunk and tail support paired lateral and tail fins. They lack organs for excretion, circulation, and respiration and are hermaphrodite.

Chaetognatha Phylum comprising the arrow worms, first encountered in the fossil record in Carboniferous rocks.