350 Mr Willis on the 



DESCRIPTION OF THE PLATES. 



Plate XXII. 



The letters of reference belonging to the shaded figures on this Plate are con- 

 tained on its accompanying outline Plate, marked Plate 22*. 

 Fig. 2 is a section of the vocal mechanism in its natural state, made by a plane, 

 technically called the mesial plane, passing through the mouth, larynx, &c. 

 and dividing the head symmetrically. In the outline of this Figure the mouth, 

 chin, tongue, &c. are sketched in to make the relative situation of the Larynx 

 to these parts more clear ; the shaded Figure is confined to the Larynx and 

 parts immediately adjacent. 



MP A, upper part of windpipe. 



MTOLIP, laryngeal cavity, opening at LI into the pharynx. 



trIL, part of the cavity of the pharynx, which is continued above tr 



into the nostrils. 

 efghHk, cavity of the mouth. 



a, b, lips, c, d, teeth, ef, palate, fg, soft palate. /(, uvula. 

 kH, tongue. LO, epiglottis. IK, oesophagus. 

 TV, vocal ligament, constituting one side or lip of the glottis^ 

 TB, upper ligament, constituting one side of the pseudo-glottis ; the dark 



opening between these is that of the ventricle. 

 PQ, DM, cut edges of cricoid cartilage. 

 ETF, cut edge of thyroid cartilage. 

 s, cut edge of arytenoi'deus transversus. 

 Fig. 1 is a section made by a plane perpendicular to the former, and passing along 

 the line AB and BC in Fig. 2 ; looking towards IK. 



The line GG passes through the vocal ligaments and glottis. 

 LL, through the superior ligaments and pseudo-glottis. 

 VV, through the two ventricles. 





