Iig.13. 



FIG. 1 7. The under side of the hyoid arches of a Raven, with the superior larynx 

 and upper part of the windpipe, in situ. Designed to show the attach- 

 ment of the muscles of the parts ; the sterno-hyoideus and the cleido- 

 trachealis are pulled outwards by dissecting hooks. Life-size, by the 

 author from his own dissections. 



FIG. 18. Superior view of the same parts, with lower muscles removed, but 

 showing those attached to the upper side of the hyoid and superior 

 larynx. The rima glottidisis represented as closed, with the arytenoids 

 in contact. The elliptical aperture, which always remains in front, is 

 closed by the upper surface of the thyroid plate beneath it. 



