BIRDS WITH TEETH. 23 



ones only adhered to the skeleton. The theory of the nakedness of the body, as 

 advocated by Professor Vogt, is not very probable, in view of the fact that the thighs 

 were feathered ; and to suppose that the rest of the body was scaly is hardly defen- 

 sible, for we may with greater right ask where the scales are than where the feathers. 

 The conclusion we gain from the above is that the oldest bird known was a land- 

 bird, and arboreal in its habits. But in spite of its feathers it can hardly have had a 

 great resemblance to the forms which now inhabit the woods. Nor is it probable that 

 it was a very expert flyer ; the broad, rounded wings and the curious tail suggest a 

 locomotion of a somewhat similar nature to the 'flight' of the flying squirrel, the 

 tail of which in fact strikingly recalls that of the Archceopteryx. 



There have been and still are authors who regard this animal as a reptile, but 

 apparently with no good foundation. If we accept the theory that the birds have 

 developed from the reptiles, the transition must have been gradual and nearly imper- 

 ceptible, so that the line to be drawn between the two classes must be more or less 

 artificial. But if Ave do not accept a feathered and warm-blooded vertebrate as a bird, 

 where then is the criterion to distinguish it from a reptile ? 



The Archceopteryx was long the only Jurassic bird known. In addition to his 

 many other discoveries of fossil birds, Professor Marsh has of late added that of an 

 American Jurassic bird, from the Atlantosaurus-beds of Wyoming, a form which in 

 1881 he described as Laopteryx prisons. The most important specimen is the poste- 

 rior portion of the skull, indicating a bird rather larger than a great blue heron. 

 Professor Marsh remarks further that in its main features the type specimen resembles 

 the skull of the Ratitae more than that of any existing birds. In the matrix attached 

 to this skull a single tooth was found, which most resembles the teeth of birds, espe- 

 cially those of Ichthyornis ; and Marsh thinks it probable that it belonged to Laop- 

 teryx, and that this bird also possessed biconcave vertebra. Like Archceopteryx, it 

 was a land-bird. 



It would be futile to attempt a reconstruction of the whole bird from the few 

 remnants on the old Cuvierian plan, since modern discoveries have proved the utter 

 failure of the method. Nobody can tell how the tail of Laopteryx was formed, and 

 when we place it with the Saururae, we do so because that position is as good as any 

 other, and because its geological age probably corresponds to that of Archceopteryx. 



LEONHABD STEJJTEGER. 



SUB-CLASS II. ODO^TOTORM^E. 



ORDER L PTEROPAPPI. 



With the exception of the Solenhofen bird, only a few scattered remains of fossil 

 birds, save from the most recent deposits, had been found prior to those startling dis- 

 coveries which afterwards were figured and described in Professor Marsh's famous 

 monograph on the extinct toothed birds of North America. Not only were the re- 

 mains of these cretaceous birds in an unusually splendid state of preservation, but they 

 reversed in many respects both the popular and the scientific ideas as to the charac- 

 ters and the origin of birds. 



As these Odontornithes, or toothed birds, form one of the most interesting and 

 important contributions to modern ornithological science, and as a thorough under- 

 standing of their remarkable structure, so different from that of any living bird, is 



