II. 



Recent Researches in Fossil Birds. 



PARTLY, perhaps, owing to the difficuhy of the subject itself, and 

 in part to the comparative scarcity of their remains, our know- 

 ledge of fossil birds has not of late years advanced at the same rapid 

 rate as has that of other branches of zoological science. The 

 appended list of works and memoirs indicates, however, that the past 

 year has been more than an average one as regards the work done in 

 this branch of research. 



The main difficulty connected with the subject of fossil birds lies 

 in the circumstance that the great majority of living members of 

 the class present such a general similarity in their plan of structure, 

 that the differences in the skeletons of the various groups are of com- 

 paratively small degree, and are totally unlike those which obtain 

 between the skeletons of the various orders of mammals and reptiles. 

 It thus happens that, although it is a comparatively easy matter to 

 assign to their proper serial position remains from the later Tertiary 

 deposits belonging to species more or less closely allied to existing 

 birds, yet when we descend lower in the geological scale and come 

 across bird-remains indicating genera unlike any now living, the task 

 of determining their affinity becomes an exceedingly difficult one. 

 Hence we find considerable discrepancy of view- as to the serial 

 position of many extinct birds, even when considerable portions of 

 their skeletons are known. 



The aim of the work standing fifth on our list was primarily to 

 revise and name the large series of bird-remains belonging to our 

 National Palaeontological Collection, but a survey was also taken of 

 the whole of the known fossil birds of Europe, exclusive of those 

 belonging to the groups of the Passeres and Picariae. It was thus 

 hoped that a definite land-mark might be established, from which 

 future researches could readily take their start. Perhaps the most 

 important point established in this work is that all the Tertiary 

 Flying Birds may be included in the primary groups into which the 

 Carinate order is subdivided by students of recent ornithology. The 

 Toothed Birds of the Cretaceous rocks of North America and Europe 

 are, however, regarded as constituting a separate series of the same 

 Carinate order, which ranks as of equivalent value with the one con- 

 taining all the modern toothless birds of flight ; this conclusion 

 being strongly supported by the view propounded by Professor D'Arcy 

 Thompson in 1890, that the gigantic American Toothed Bird known 



