34 



NATURE 



[November 12, 1891 



group of vertebrate fossils known ; indeed, it is only within 

 the last thirty-five years that any considerable number of 

 species had been recorded. 



That the existence of birds at the period of the 

 Secondary rocks should have been first intimated by their 

 foot-prints may seem strange ; but as far back as 1835 a 

 notice appeared in Sillhnaiis American Journal of 

 Science stating that Dr. Deane had discovered ifn- 

 pressions resembling the feet of birds upon some slabs of 

 Triassic sandstone from Connecticut. Dr. Hitchcock, 

 who was the first to submit these tracks to careful scien- 

 tific examination, concluded that they had been produced 

 by the feet of birds which must have been at least four 

 times larger than an ostrich. The great size of some of 

 these foot-prints, however, presented at the time an 

 obstacle to their acceptance, notwithstanding the fact of 

 their exhibiting the same characteristic number of toe- 

 joints as exist in the feet of living tridactylous birds — 

 namely, three phalangeal bones for the inner toe, four for 

 the middle, and five for the outer one. 



The subsequent discovery of the entire skeletons of 

 great wingless birds in New Zealand has, to some extent, 

 destroyed the force of this objection as to their size ; 

 nevertheless, it seems more probable that these im- 

 pressions were made by some of those gigantic Dino- 

 saurs whose remains have been in later years met with in 

 such abundance in the Secondary rocks of the American 

 continent, many of which were bipedal in their method of 

 progression, their fore-limbs being exceedingly short, and 

 but ill adapted for use in walking. The hind-foot in 

 Iguanodon and in some others was tridactylous, and 

 agreed in the number of toe-bones with the foot of the 

 Dinornis and other flightless birds. But between the 

 discovery of the reputed foot-prints of birds in the Con- 

 necticut Valley sandstones, and the finding of true bird- 

 remains in Secondary rocks, a long interval of time has 

 elapsed. Some supposed bird-bones from the Chalk of 

 Burham, near Maidstone, were figured and described as 

 long ago as 1845 by Dr. Bowerbank, under the name of 

 Cimoliornis, but these proved to belong to a gigantic 

 Pterodactyle, and not to an albatross. The same fate 

 befell Dr. Mantell's Wealden bird {Palceornis cliftii, 

 1844), now also transferred to the Ornithosauria by Mr. 

 Lydekker. 



Passing over some fragmentary remains, discovered in 

 1858 by Mr. Lucas Barrett in the Greensand of Cam- 

 bridge, referred to birds, we come in 1861 to the dis- 

 covery, announced by Dr. H. von Meyer, of the impression 

 of a single feather upon a slab of lithographic stone from 

 Solenhofen, Bavaria, followed in 1862 by the description 

 by Prof, Owen of the skeleton of a remarkable long- 

 tailed bird from the same formation and locality, the 

 ArchcEopteryx macrura. This, which is still the earliest- 

 known avian fossil, is also the most generalized bird 

 known ; and the discovery, twenty years later, of a second 

 example only serves to confirm the correctness of the con- 

 clusions which had been arrived at from a study of the 

 first-found example. 



That it was clothed in feathers serves to prove the true 

 avian character of the fossil, no reptile having been met 

 with possessed of such epidermal structures. The remark- 

 able features are that the jaws were armed with conical 

 enamelled teeth implanted in distinct alveoli (see Fig. i) ; 

 the three metacarpals in the manus are separate and the 

 phalanges are free (not anchylosed, as in modern birds), 

 and each of the three digits was armed with a terminal 

 claw ; the centra of the vertebrae are amphicoelous ; 

 there are twenty free vertebras in the tail, which is longer 

 than the body, each vertebra bearing a pair of feathers, 

 and the tail does not terminate in a pygostyle, like most 

 modern birds. 



From these, and other anatomical characters, Archceo- 

 f)teryx has been placed in a distinct order, the Saurur^, 

 or lizard-tailed birds. 



NO. I I 50, VOL. 45] 



The next important bird discoveries from the Secondary 

 rocks were those made in North America by Prof. O. C, 

 Marsh, in 1870, from the Upper Cretaceous strata of 

 Kansas, U.S., by which we became acquainted with two 

 most distinct and important types, the Hesperornis and 

 the Ichthyornis. Both of these birds are remarkable as 

 having their jaws armed with teeth. The former {Hesper- 

 ornis) had the teeth implanted in grooves, it had only 

 rudimentary wings, a flat keel-less sternum, and saddle- 

 shaped vertebras. It was a huge fish-eating diver, nearly 

 6 feet high, probably resembling in appearance the loons 

 and grebes (see Fig. 2). 



The latter {Ichthyornis) was a bird of powerful flight, 

 having well-developed wings and a strongly-keeled 

 sternum ; its jaws were armed with teeth in distinct 

 sockets, and the vertebras were biconcave (see Fig. 3), 



By far the greater proportion of avian remains 

 known are of Tertiary age ; many are referable to 

 existing birds, but a it.Mi of them are of almost as 

 great interest to the ornithologist as those already re- 

 ferred to, either as representing, like them, extinct forms, 

 or because they tell of important changes during Tertiary 

 times in the geographical distribution of many genera of 

 birds. The oldest of these remains have been obtained 

 from the London Clay, A single skull of a large ostrich- 

 like bird was obtained from the Lower Eocene of the Isle 

 of Sheppey, and described by Owen in 1869 under the 

 name of Dasornis londiniensis. Two limb-bones of a 

 bird as large as an ostrich, but more robust, and with 

 afifinities to the Anserine type, as well as to the Ratitiis, 

 were obtained about six years ago from the Lower Eocene 

 near Croydon, and described by Mr. Newton under the 

 name of Gastornis klaasseni. Two other species of Gast- 

 ornis had previously been described from the Eocene of 

 Meudon and Rheims, in France, so that the Ratitae were 

 doubtless well represented in Western Europe in Tertiary 

 times. 



Another remarkable discovery in the London Clay of 

 Sheppey is that of the Odotitoptcryx toliapicus, a bird 

 with a powerfully serrated bill, well adapted for seizing 

 fish, which probably formed its prey. 



The interest attaching to the discovery, fifty years ago, 

 of the bones of extinct ostrich-like birds in New Zealand, 

 remains unabated ; their former abundance may be ima- 

 gined from the fact that there is hardly a museum in the 

 world where remains of the " moa " are not to be found, 

 and they still continue to be sent to Europe for sale. 

 The series of skeletons of Dinornis set up in the Vienna 

 Museum is even finer than that in the British Museum. 

 In the latter, six almost complete skeletons may be seen, 

 beside an immense series of detached bones (see Fig. 4). 

 The tallest skeleton is probably 10 feet, and the smallest 

 4 feet in height. Specimens showing the skin and feathers 

 still attached to the bones are also preserved, evidencing 

 the comparatively modern date at which they were exter- 

 minated. 



Another island, which possessed a now extinct flightless 

 bird, is Madagascar. Bones and eggs of this great bird, 

 the AF.pyornis, which probably rivalled the Dinornis in 

 size, are preserved in the British Museum ; but, owing to 

 the lack of exploration in the island, we know as yet of only 

 a few odd bones, where entire skeletons doubtless exist, 

 perhaps as abundantly as in New Zealand. The t.g% of 

 ^pyornis is the largest bird's &gg known, its liquid 

 contents being rather more than two gallons. 



The close affinity existing between birds and reptiles 

 has long ago been an accepted fact in zoology ; the find- 

 ing, therefore, of such primitive birds as Archaopteryx, 

 Hesperornis, and Ichthyornis on the one hand, and of 

 the numerous bird-like IJinosaurs in Europe and America 

 on the other — indeed, the whole tendency of this branch of 

 modern pa] geontological discovery— has been to strengthen 

 the relationship of the two, and to confirm their association 

 in one primary group of the Vertebrata, theSAUROPSlDA. 



