EXPLANATION OF THE PLATE 



The figures represent dissections of the syrinx or organ of 

 voice of the Hooded Crow, Gorvus comix, L., drawn from 

 nature and slightly diagrammatic. 



Fig. 1. — The lower end of the trachea and upper end of the left 

 bronchus viewed from the side : a portion of the outer wall of 

 the syrinx and bronchus has been removed, so as to expose 

 the Membrana semilunaris (M.s.) and the Membrana tympani- 

 formis interna (M.t.i.). 



M.S. Membrana semilunaris. 



M.t.i. ,, tympaniformis interna. 



R. Right bronchus. 



L. Left bronchus. 



E. Tracheal rings extended. 



C. ,, ,, contracted. 



Fig. 2. — A portion of the outer wall of Fig. 1, seen from the 

 inside, and showing the fleshy fold F. 



Fig. 3. — The lower end of the trachea and upper end of the left 

 bronchus viewed from the side, showing the origin and inser- 

 tion of the principal muscles. 



Br. 11. Bronchial ring 11. 



Br. III. „ „ III. 



M.t.e. Membrana tympana externa. 



S.t. Sterno-trachealis muscle. 



T.b.v. Tracheo-bronchialis ventralis muscle. 



T.h.d.l. ,, , dorsalis longus muscle. 



T.b.o. ,, ,, obliquus muscle. 



S.d. Syringeus dorsalis muscle. 



S.v. ,, ventrilateralis muscle. 



