CONTENTS. 



I. HiSTOEICAL EeMAEKS ON THE DISTINCTION BETWEEN SiNGING BiRDS AND OTHER 



Passerines, founded on their Vocal Muscles ...... i 



II. Review of the Genera the Larynges of which have been already examined 5 



III. New Investigations into the Arrangement of the Vocal Muscles, in the 



Old and New World forms 9 



IV. Account of Observed Forms of Laeynx : 



(i) Organ of Voice of Chasmarhynchus . . . . . . . .21 



24 

 25 

 27 

 29 



(ii) Organ of Voice of the Piprinae ........ 



(ili) Organ of Voice of the Ampelinae and Ewylainiiiiae .... 



(iv) Organ of Voice of the Tyranninae and Fluvicolinae .... 



(v) Organ of Voice of the Todinae and Platyrhynchinae, Cab. 



(vi) Organ of Voice of the Myiotherinae, Scytalopinae, Anabatinae, and Dendro- 



colaptinae ............ 30 



(vii) Organ of Voice of Trochilus . . . . . . . . -37 



(viii) Organ of Voice of Colius . . . . . . . . . .37 



V. On the Relations between the Structure of the Organ of Voice, and the 



External Characters of the Passerines 38 



VI. General Remarks on the Classification of the Passerines . . . -4^ 

 Remarks .............. co 



Description of the Fiuuebs -54 



Addendum to Muller's paper on the Vocal Organs of Passerine Birds . . 61 



Appendix containing a Description of the Vocal Organs of some aberrant Passerine 



Birds not recorded by Mullee ......... 63 



