CHAPTER VII 



THE RESPIRATORY ORGANS 



The Larynx and Trachea. In the Crocodilia 

 the framework of the larynx consists of three 

 cartilages, of which two represent the arytenoids 

 of the Mammalia ; the third represents the thyroid 

 and cricoid of mammals. The last is considerably 

 larger than the first and is a broad closed ring, dif- 

 fering in form in the different species. In spite of 

 the fact that some of them have a voice, the vocal 

 cords, according to Bronn, are wanting in the 

 Crocodilia. According to Henle the vocal appara- 

 tus is produced by the projection into the laryngeal 

 cavity of the inner border of the small arytenoid 

 cartilages and by the infolding, under these carti- 

 lages, of the mucous membrane of the larynx; this 

 forms the thick but fairly free folds that, when the 

 glottis is narrowed, are well adapted to produce 

 the harsh tone of the animal. 



The epiglottis is absent in the Crocodilia. 



In many Crocodilia (C. vulgaris, for example) 

 the trachea, Fig. 57, tr, forms a loop which begins 



in some species before hatching, in other species not 



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