First he failed to see the great structural difference between the penguins (which Illiger had placed as a group, Impennes, of equal rank to his other families) and the auks, divers and grebes, Pygopodes - combining all of them to form a "Typus " (to use his term) Urinatores; and secondly he admitted among the Natatores, though as a distinct " Typus " Podoidae, the genera Podoa and Fulica, which are now known to belong to the Rallidae - the latter indeed (see Cool') being but very slightly removed from the moorhen (q.v.).
The Rallidae present the very noteworthy woodhens, Ocydromus, and the takahe, Notornis, which is almost extinct.