A group of worm-like, marine, burrowing animals, known from Cambrian times and ranging up to the present. There is dispute concerning relationships. Some authorities believe the body cavity is a pseudocoelom and the group should be included in the Aschelminthes; others believe it is a coelom and the group should be given phylum status. Priapus worms have stout, cucumber-shaped bodies. There is a spined, eversible proboscis used to capture prey. The trunk is superficially segmented and bears peculiar posterior tentacles that may have a respiratory function.
Subjects: Zoology and Animal Sciences.