Phoronis is a genus of the horseshoe worm family (Phoronidae), in the phylum Phoronida. Phoronis may also refer to: Various species in the above genus: Phoronis australis Phoronis ovalis Phoronis psammophila Phoronis (c. 7th-6th c. BC), an ancient Greek epic poem which told the story of the mythological hero Phoroneus. Phoronis (5th c. BC), a lost work by the Greek historian Hellanicus. Phoronis, a name for Io, the sister (or descendant) of Phoroneus.