Priapulida (priapulid worms or penis worms, from Gr. πριάπος, priāpos `Priapus` + Lat. -ul-, diminutive) is a phylum of marine worms. The name of the phylum relates to the Greek god of fertility, because their general shape and their extensible spiny introvert (eversible proboscis) may recall the shape of a penis. They live in the mud (w.....