FOSSIL FORMS.] B I B D S 729 stands alone, and all that can be said in the latter respect is, that the form of its feet indicates a bird given to a more or less arboreal life. It is not easy to imagine the use in FIG. 39, Portiun of the slab containing remains of Archceopteryjc, showing the extremity of the tail, with a pair of feathers springing from each vertebra. Natural Size. the bearer s economy of its singular tail, which one would think must have been a clumsy appendage, and this notion is perhaps justified by the certainty that similar tails had gone out of fashion when the next birds known to have existed flourished. These are from the Cretaceous formation, and as in that freshwater-deposits are few in number, it is not surprising that true ornithic remains are in them exceedingly rare. Many fossils that were formerly thought to have been the remains of Birds have since been determined as belonging to Reptiles (Pterodactyls), among them the Cimoliornis diomedea, from the Chalk of Maidstone, which Dr Bower- bank has not hesitated to refer to his Pterodactylus gigan- teus. But in 1858 Barrett discovered, in the Upper Green- sand of Cambridge, remains described by Mr Seeley in I860 (Ann. and Mag. Nat. Hist. ser. 3, xviii. p. 100) under the name of Pelagornis barretti, which, we must bear in mind, has nothing to do with the genus Pelagornis established by M. Lartet (Comptes Rendus, 1857, p. 740), and these remains, renamed Enaliornis in 18G9 by Mr Seeley (Index to Hep. on Second. Reptiles, &c.), seem to be those of a real Bird, having some resemblance to a Penguin. Belonging to the same epoch also Bird-fossils have been foiind by Professor Marsh in the United States of America, and they have been referred to at least six genera Apatornis, Gracidavus (4 spp.), Ilesperornis, Ichthyornis, Laornis, Palceotringa (3 spp.), and Telmat- ornis (2 spp.) The first and fourth of these were about as large as a Pigeon, or larger, are from the Cretaceous shale of Kansas, and differ from all known Birds in having biconcave vertebne and, possibly, teeth, whence the latter has been made the type of a distinct Subclass, to which the name of Odontornithes is applied. The second belongs to the Steganopodes; the third seems to have been related to the Colymbidce. The affinities of the fifth have not yet been determined ; it was nearly as large as a Swan, and its remains were discovered in the Middle Marl of New Jersey. The sixth was apparently one of the Limicolce; and the seventh was probably allied to the Rallidce. The Eocene period furnished a still greater number of Eocene ornitholites. First, perhaps, in bulk is that known as Gast- Birds. ornis parisiensis, found by M. Gaston Plants, and soon after by M. Hebert, in a conglomerate beneath the Plastic Clay of Bas-Meudon. Much difference of opinion obtains as to the affinities of this Bird, which was at least as large as an Ostrich ; but M. Alphonse Milne-Edwards, 1 after re viewing the evidence of others and studying the specimens obtained, considers it (Diet. Univ. d llist. Nat. ed. 2, May 1869) most nearly allied to the Anatidce, from which, how ever, it differs in so many important characters that it cannot be included among them according to any taxo- nomic scheme as yet proposed. One may presume, he adds, that it was incapable of flight, though able to swim. Other birds of huge stature lived at a time not much later. Dr Bowerbank has referred the fragment of a tibia from Sheppey, which was a little smaller than that of an Emeu, to a genus Lithornis. On this Mr Seeley lias founded his Megalornis, the Lithornis to which Professor Owen, in 1841, had applied the former name, being regarded as re sembling a Vulture. This naturalist has also described the fragmentary cranium of a large Bird, combining Dinornithic. and Struthious characters, from the same locality, under the name of Dasornis (Tr. Zool. Soc. vii. p. 145), and he has further added from Sheppey (Quart. Journ. Geol. Soc. xxix. p. 511) a yet more remarkable form to those previously known from Britain, in the Odontopteryx toliapicus FIG. 40. Remains of head of Odontopteryx, from the original in the British Museum; side view ; natural size. a creature having its jaws armed with osseous denticulations, and in this respect unlike Professor Marsh s Ichthyornis, FIG. 41. Itemains of head of Odontopteryx, seen from above. concluding that it was a warm-blooded, feathered, and winged biped, web-footed, and a fish-eater. From Sheppey, i The writer cannot name tins distinguished naturalist without acknowledging the very many tokens of friendship received at his hands in connection with the present suliject, while the summary of fossil ornithology here given is in a great measure due to the article cited in the text a few lines further on. Further details are taken from his magnificent Recherches Anhtomiques et Paleontologiqucs pour servir d I histoire dcs Oiseaux Fossiles de la France, Paris, 1867-71. The writer has also to express his thanks to Mr Seeley for valuable assistance in this portion of the article.
III. 92