APPENDIX 



ON THE VOCAL ORGAN OF SINGING BIRDS 



MY friend Mr. W. P. Pycraft, of the Oxford Museum, 

 has been kind enough to provide me with the drawings 

 reproduced on the accompanying plate, to illustrate the 

 nature of the vocal apparatus as briefly explained on p. 

 125 foil. They are not intended to represent the com- 

 plete result of Mr. Pycraft's researches, which are now 

 in progress, but are only meant to give the reader some 

 idea of (1) how the musical sound is generated, (2) how 

 it is modified in pitch at the will of the bird. I have 

 myself had the advantage of examining some of Mr. 

 Pycraft's dissections ; and in order to make more sure of 

 my ground on the musical side of the question, I called 

 in the aid of Mr. F. Cunningham Woods, Mus. Bac. of 

 Exeter College, who made some valuable suggestions, as 

 will be seen below. The trachea and syrinx of birds 

 have often been minutely examined by anatomists, and 

 accounts will be found not only in the usual text-books, 

 but in Macgillivray's British Birds (Introduction to vol. 

 ii.), in Dr. Coues' Field and General Ornitfiology, and in 

 Mr. Shufeldt's Myology of the Raven. These works, how- 

 ever, did not explain to me very clearly how the 

 musical sound is originated. The help of Mr. Pycraft 

 and Mr. Woods has cleared up some difficulties that 

 presented themselves ; but I confess that I am still un- 



