After Parker, 1982
<==o Polyxenida |--o Synxenoidea | `-- Synxenidae `--o Polyxenoidea |-- Polyxenidae |-- Lophoproctidae `-- Hypogexenidae
Reference(s):
- Lahti, S., Malmström, K. K., Koli, L., Leikola, A., Syrjämäki, J. & Lahti, J., 1980: Zoo, Suuri Eläinkirja 6: Selkärangattomat.
–Werner Söderström Osakeyhtiö, Porvoo-Helsinki-Juva, 1980.
Original work [in French]: Beaut, Du Monde Animal XI & XII Invertébrés.
–Rizzoli Editore, Milano, 1968. - Parker, S. P. (ed.), 1982: Synopsis and classification of living organisms. Vols. 1 & 2
–McGrew-Hill Book Company