4 Distinction between Singing Birds and other Passerines. 



have followed them ; and although Wag-ler in his Classification of Birds has made but 

 little use of Nitzseh's work, he has called Nitzsch the Master of Ornithologists, so far 

 has his authority extended. 



Later on, Blyth ^ put forward views similar to those of Nitzsch, as to the necessity 

 of sejjarating the Singing Birds from the false Passerines. As the internal differences 

 between Singing Birds and the Picariae were regarded as thoroughly established, several 

 ornithologists directed their energies to discovering the external differences between these 

 divisions. Keyserling and Blasius^ fancied that they could recognise a striking difference 

 in the covering of the feet of the Singing Birds and Picariae; and indeed, within certain 

 limits, this peculiarity does enable us to form conclusions as to internal structure. The 

 exceptions, which Burmeister ' pointed out, may for the greater part be disregarded, as 

 the genera which appear to form the exceptions were, for the most part, wrongly classified 

 by Nitzsch. But the birds whose larynges I have examined offer some very striking and 

 inexplicable exceptions to the law discovered by Keyserling and Blasius, and in these eases 

 as to the structure of the larynx, a wrong conclusion would be arrived at from the characters 

 of the foot. I shall return to this subject in the systematic portion of this treatise. 



Sundevall has lately discovered a difference in the arrangement of the wing feathers, 

 and has made use of it in the separation of Singing Birds and Picariae {Coccyges Sund.) ; 

 this difference may have its value, as a characteristic of families and genera, but can 

 possess no greater. The separation of Singing Birds and Picariae, according to an internal 

 difference described by Nitzsch, is untenable for a large number of genera, after my re- 

 searches into the organ of voice and other parts. The vocal organ in the Passerine birds 

 is by no means so exactly constructed upon two principal types, for there are no doubt 

 a greater number of peculiar forms, the most important variations of which are as yet 

 unknown; and it will be only after a complete knowledge of these that the question of 

 the classification of the Passerines can be again taken up with success. Later classifications 

 of birds are no better than those of Nitzsch. Vieillot, Cuvier, Temminek, Vigors, Swainson, 

 Wagler, Boie, and Gray have done excellent work in increasing our knowledge of the 

 genera of birds, but their classifications are not based upon scientific principles; they 

 bring birds together into a family according only to their own opinions, so that we 

 can scarcely wonder at their families being of no more value than irrational groups 

 without characters, nor that these groups vary wnth different authors. The works 



> Mag. Nat. Hist. Vol. II. 



' Wiegraann's Arcliiv, 1839, I. 332. K. and B. die Wirbeltliiere Europa's, 1840. 



' Wiegmann's Archiv, 1840, I. 220. Cf. K. and B. ibid. p. 362. 



