EXPLANATION OF THE PLATE 



The figures represent dissections of the syrinx or organ of 

 voice of the Hooded Crow, Corvus 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. II. Bronchial ring II. 



Br. III. III. 



M.t.e. Membrana tympana externa. 



S.t. Sterno-trachealis muscle. 



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



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



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



S.d. Syringeus dorsalis muscle. 



S.v. ventrilateralis muscle. 



