THE RABBIT. 337 



Examine first the cartilages and then the soft parts, making 

 out : 



374. The thyroid (Fig. 64, th), a large plate of cartilage, consisting 

 of right and left alae united to one another ventrally at an obtuse 

 angle : dorsally each alse is produced into anterior and posterior 

 cornua, small processes, the posterior of which articulates with a facet 

 on the cricoid. 



375. The cricoid (cr], an annular cartilage, narrow ventrally, wide 

 dorsally, situated immediately behind the thyroid, the posterior cornua 

 of which articulate with facets on the dorso-lateral regions of its outer 

 surface : ventrally there is a considerable interval between the thyroid 

 and the cricoid, bridged over by the crico-thyroid membrane 

 (cr.th.ni). 



The anterior ring of the trachea -is often more or less transitional 

 between the ordinary tracheal rings and the eric aid. 



376. The arytenoids (ary\, paired triangular cartilages articulated 

 to facets in the postero-dorsal region of the anterior edge of the 

 cricoid. 



377. The cartilage of Santorini, small paired nodules embedded in 

 the cornicula laryngis (e.ld). 



378. The epiglottis (epg), an obcordate plate of cartilage attached 

 by its narrow ventral end to a facet on the inner surface of the ventral 

 region of the thyroid. 



379. The reddish mucous membrane lining the larynx, continuous 

 behind with that of the trachea and in front with that of the pharynx. 



380. The ventricles of the larynx (v./a), paired shallow de- 

 pressions on its inner surface at about the level of the arytenoids. 



381. The vocal cords (v.c), paired folds of mucous membrane 

 forming the posterior boundaries of the two ventricles and supported by 

 ligaments : they extend from the arytenoids downwards to the inner face 

 of the thyroid, where they are attached close together just posterior to the 

 facet for the epiglottis. 



382. The false vocal cords (f.v.f), similar folds forming the anterior 

 boundaries of the ventricles. 



383. The crico-thyroid muscles, arising one on each side from the 

 outer surface of the cricoid, and passing forwards and upwards to be 

 inserted into the thyro'd, which they serve to depress. 



384. The posterior crico-arytenoid muscles, large paired muscles 

 covering the dorsal surface of the cricoid, from which they arise, and 

 passing outwards and forwards to be inserted into the arytenoids. 



385. The arytenoid muscles, situated immedia'ely anterior to the 



Z 



