(I) Amphicoelous; each end of the centrum is concave; this, the lowest condition, is embryonic, but was retained in Archaeopteryx and in the thoracic vertebrae of Ichthyornis.
Such a pygostyle is absent in Archaeopteryx, Hesperornis, Tinami and Ratitae, but it occurs individually in old specimens of the ostrich and the kiwi.
Reduction of the number of toes (the fifth shows no traces whatever, not even in Archaeopteryx) begins with the hallux, which is completely or partly absent in many birds; the second toe is absent in Struthio only.
Dames, " Uber Brustbein Schulterand Beckengi.irtel der Archaeopteryx," Math.
A wide gap separates Archaeopteryx from the next order of fossil birds of the Cretaceous epoch, and, since freshwater deposits of that age are rare, bird remains are uncommon.
Owen com municated a detailed description of them to the Philosophical Transactions (1863, pp. 33-47), proving their bird-like nature, and referring them to the genus Archaeopteryx of Hermann von Meyer, hitherto known only by the impression of a single feather from the same geological beds.
It was quickly seen - even by those who held Archaeopteryx to be a reptile - that it was a form intermediate between existing birds and existing reptiles; while those who were convinced by Sir R.
Unfortunately none of these, however, can be compared for singularity with Archaeopteryx or with some American fossil forms next to be noticed, for their particular It is true that from the time of Buffon, though he scorned any regular classification, geographical distribution had been occasionally held to have something to do with systematic arrangement; but the way in which the two were related was never clearly put forth, though people who could read between the lines might have guessed the secret from Darwin's Journal of Researches, as well as from his introduction to the Zoology of the " Beagle" Voyage.
Marsh states that he had fully satisfied himself that Archaeopteryx belonged to the Odontornithes, which he thought it advisable for the present to regard as a subclass, separated into three orders - Odontolcae, Odontotormae and Saururae - all well marked, but evidently not of equal rank, the last being clearly much more widely distinguished from the first two than they are from one another.
The separation of the Ratitae from the other birds, and their seemingly fundamental differences, notably the absence of the keel and of the power of flight, induced certain authors to go so far as to derive the Ratitae from the Dinosaurian reptiles, whilst Archaeopteryx (q.v.) and the Carinatae were supposed to have sprung from some Pterosaurian or similar reptilian stock.
Finally the presence of the flying lizards (Pterydactylus, Rhamphorhynchus) and the ancient birds (Archaeopteryx) is determined from remains in a most wonderful state of preservation in these ancient deposits.
Especially noteworthy was the discovery of birds with teeth both in Europe (Archaeopteryx) and in North America (Hesperornis), of Eocene stages in the history of the horse, and of the giant dinosauria of the Jurassic and Cretaceous in North America.
The name of Archaeopteryx litho graphica was based by Hermann von Meyer upon a feather (Gr.irrEpv, wing) found in 1861 in the lithographic slate quarries of Solenhofen in Bavaria, the geological horizon being that of the Kimmeridge clay of the Upper Oolite or Jurassic system.
Archaeopteryx was a bird, without any doubt, but still with so many low, essentially reptilian characters that it forms a link between these two classes.
Haeckel established the subclass Saururae, containing solely Archaeopteryx, in opposition to the Ornithurae, comprising all the other birds.
The importance of Archaeopteryx justifies the following descriptive detail.
The clawed slender fingers did not make Archaeopteryx any more quadrupedal or bat-like in its habits than is a kestrel hawk, with its equally large, or even larger thumb-claw.
Owen, "On the Archaeopteryx von Meyer.
Huxley, "Remarks on the Skeleton of the Archaeopteryx and on the relations of the bird to the reptile," Geol.
Dames, "U ber Archaeopteryx," Palaeontol.
(Berlin, 1884); Idem, " L ber Brustbein Schulterand Beckengiirtel der Archaeopteryx," Math.