159 



THE CLASSIFICATION OF BIRDS 



PnoFESSOE Newton's article 'Ornithology' in the 'En- 

 cyclopaedia Britannica,' and the preliminary sketch of Dr. 

 Gadow in Bronn's ' Thierreich,' contain a digest of, and 

 criticisms upon, the main schemes -of classification of this 

 group which have as yet appeared. I shall, therefore, refer 

 the reader to those works for the history of the subject. 

 There can be no. question, in my opinion, that birds must 

 be primarily divided into two great' divisions, viz. Saururae 

 and Ornithurse, the first to contain Arcliaopteryx and possibly 

 Laopteryx, the latter the rest of birds, both living and extinct. 

 As to the OrnithursB, while there is a very general agreement 

 with the main subdivisions — no one probably will quarrel 

 seriously with the divisions adopted in the present work — 

 no one has (to my mind) satisfactorily arranged the different 

 groups with reference to each other. More especially does 

 it appear to me that the majority of ornithologists are in 

 error concerning the position of the picarian and passerine 

 birds. 



In considering a scheme of classification it is clear that 

 we must bear in mind indications of the descent of birds. 

 Existing schemes have savoured too much of a Jtnere sorting 

 by combining in various ways characters which are dis- 

 tinctively bird characters. However unsuccessful the con- 

 struction of phylogenetic trees has been, it is abundantly 

 plain that that must be the line to take in arranging a group 

 scientifically. It follows, therefore, that in sketching, at 

 any rate, the main outlines of our scheme attention must 

 be paid only, or chiefly, to those characters which birds 

 have inherited from their reptilian ancestors. 



