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.
Subjects: Zoology and Animal Sciences — Ecology and Conservation.