398 DR. C. F. SONNTAG ON THE ANATOMy, 



Larynx* : — The thyroid cartilage is shaped somewhat differently 

 from that in Man, for it has median notches both above and below. 

 The angle between itsalae is about 90°. Its superior and inferior 

 cornua articulate, as in Man, Avith the hyoid bone and cricoid 

 cartilage. The cricoid cartilage is as in Man. The arytenoid 

 cartilage is shaped as in Man, and the cartilages of Santorini and 

 Wrisberg are very small. The epiglottis has the same shape as in 

 Man. It is small and does not rise freely above the level of the 

 aryteno-epiglottidean folds. The true vocal cords are attached to 

 the thyroid alae and vocal processes of the arytenoid cartilages. 

 They are soft and flaccid, consisting almost entirely of mucous 

 membrane, and a little elastic tissue. The false cords are 

 likewise soft, and between them there are well-marked ventricles. 

 The latter extend upwards behind the false cords to the 

 aryteno-epiglottidean folds, and they are prolonged upwards by 

 well-marked diverticula to the air-sac, which begins above at the 

 excavated hyoid bone and extends downwards even into the 

 axillae. The cervical part of the pouch has alres-dy been 

 described. This pouch is much larger than that described in 

 many other animals, and resembles that in Simia in its extent. 

 The communications between the sac and ventricles pierce the 

 thyro-hyoid membrane, which is large. The crico-thyroid 

 viemhrane is as in Man. The laryngeal joints (crico-thyroid, 

 thyro-hyoid, crico-arytenoid) are as in Man. 



Laryngeal Muscles : — The thyro-hyoid muscle runs from the 

 lower half of the thyroid ala to the lower border of the hyoid 

 bone. The crico-thyroid muscle runs from the anterior two-thirds 

 of the lower border and outer surface of the cricoid cartilage to 

 the lower border of the thyroid cartilage anterior to the inferior 

 cornu. It is not fan-shaped as in Man. The posterior crico- 

 arytenoid muscle arises from the posterior cricoid lamina, and is 

 inserted into the processus muscularis of the arytenoid. It is 

 more vertical and not so fan-shaped as in Man, and a small 

 branch of the superior thyroid artery runs on its posterior 

 surface. The lateral crico-arytenoid muscle runs from the upper 

 border of the lateral part of the anterior cricoid arch to the 

 processus muscularis. The thyro-arytenoid muscle does not divide 

 as in Man. It runs from the inner surface of tlie thyroid ala in 

 its lower half, near the mid plane, to the outer border of the 

 arytenoid cartilage above the crico-arytenoid. The oblique and 

 transverse arytenoid muscles are as in Man, but are diminutive, 

 as is the ary-epiglottidean muscle. 



Inte7-ior of the Larynx : — The ary-epiglottic folds are almost 

 absent. Posteriorly the cuneiform tubercles and tubercles of 

 Santorini are close together. The pyriform sinus is more 

 marked than in Man. The upper division of the larynx is 

 shallow, and the cushion of the epiglottis is well marked. The 

 middle division is relatively larger than in Man. The false cords 

 are 4 mm. apart. The lower part of the cavity is as in Man. 



* Excellent illustrations liave been published by Gratiolet (22). 



