THB CliASSIFIOATIOIJ Or BIEDS. - 255 



The principal schemes for the classification of Birds which 

 have appeared since Ouvier's are those which have been pro- 

 pounded by Lilljeborg \ Huxley % Sundevall ', Garrod*,Sclater ', 

 Newton ', Eeichenow ', Stejneger °, Piirbringer °, Seebohm ^°, 

 Gadow ", and Sharpe ". 



Mr. Henry Seebohm deserves exceptional credit for having 

 given us a classification founded on absolute diagnostic 

 characters, by which, for the first time perhaps, the definite 

 characteristics of the leading groups of Birds have been 

 clearly summarized. On this account we gladly avail our- 

 selves largely of his labours, and follow his grouping to a 

 very great extent. 



We will shortly proceed to enumerate the principal groups 

 into which we think the Class of Birds is thus divisible, and to 

 give the characters of such leading groups. The classification 

 here offered is, however, put forward only in a tentative manner 

 and with much diffidence, as one which we think may be found 

 practically useful. But, before we proceed to the enumeration 

 of the groups, we would endeavour to stimulate and arouse the 

 interest of the Student by pointing out some striking examples 

 of errors into which we should fall, if we rested content with 

 merely superficial characters, such as we have mainly referred to 

 in our introductory chapter. 



Birds may be shortly defined as feathered animals, since no 

 other animals possess such structures. They are, however. 

 Vertebrate animals with warm blood and anterior limbs 

 peculiarly modified. The skull always articulates with the 

 vertebral column by a single occipital condyle ", and the lower 



I Proe. Zool. Soo. 1866. ^ P. Z. S. 1867. 



^ 'Methodi Naturalis Avium Disponendarum Tentamen,' Stockholm, 

 1872. 



* P. Z. S. 1873 and 1874. " Ibis, 1880. 



* Eney. Brit., Art. " Ornithology " (wherein a full and admirable account 

 of the history of the science and of the works of its promoters is to be found). 



' Die Vogel d. Zoolog. Garten, 1882. 



' Standard Nat. Hist., Aves, 1885. 



' Morphologie u. System, der "Vogel, 1888. 



" ' Classification of Birds,' E. H. Porter, 1890. 



II P. Z. S. 1889, and Bronn's Thierreioh, Aves, 1890. Also a paper read 

 before the Zoological Society while these pages were being revised for press 

 —March, 1892. 



'^ 'A Review of recent attempts to-classify Birds,' 1891. 

 '' By which character Birds differ from man and beasts, where there are 

 two occipital condyles. 



