Almost all the existing orders of _Birds_, if not all, are represented in the Eocene deposits by remains often very closely allied to existing types. Thus, amongst the Swimming Birds (_Natatores_) we find examples of forms allied to the living Pelicans and Mergansers; amongst the Waders (_Grallatores_) we have birds resembling the Ibis (the _Numenius gypsorum_ of the Paris basin); amongst the Running Birds (_Cursores_) we meet with the great _Gastornis Parisiensis_, which equalled the African Ostrich in height, and the still more gigantic _Dasornis Londinensis_; remains of a Partridge represent the Scratching Birds (_Rasores_); the American Eocene has yielded the bones of one of the Climbing Birds (_Scansores_), apparently referable to the Woodpeckers; the _Protornis Glarisiensis_ of the Eocene Schists of Glaris is the oldest known example of the Perching Birds (_Insessores_); and the Birds of Prey (_Raptores_) are represented by Vultures, Owls, and Hawks. The toothed Birds of the Upper Cretaceous are no longer known to exist; but Professor Owen has recently described from the London Clay the skull of a very remarkable Bird, in which there is, at any rate, an approximation to the structure of _Ichthyornis_ and _Hesperornis_. The bird in question has been named the _Odontopteryx totiapicus_, its generic title being derived from the very remarkable characters of its jaws. In this singular form (fig. 227) the margins of both jaws are furnished with tooth-like denticulations, which differ from true teeth in being actually portions of the bony substance of the jaw itself, with which they are continuous, and which were probably encased by extensions of the horny sheath of the bill. These tooth-like processes are of two sizes, the larger ones being comparable to canines; and they are all directed forwards, and have a triangular or compressed conical form. From a careful consideration of all the discovered remains of this bird, Professor Owen concludes that "_Odontopteryx_ was a warm-blooded feathered biped, with wings; and further, that it was web-footed and a fish-eater, and that in the catching of its slippery prey it was assisted by this Pterosauroid armature of its jaws." Upon the whole, _Odontopteryx_ would appear to be most nearly related to the family of the Geese (_Anserinoe_) or Ducks (_Anatidoe_); but the extension of the bony substance of the jaws into tooth-like processes is an entirely unique character, in which it stands quite alone. [Illustration: Fig. 227.--Skull of _Odontopteryx toliapicus restored. (After Owen.)]