284 



COMPARATIVE ANATOMY 



on either side of the glottis as well as by a ring-shaped cricoid 

 cartilage, from which delicate processes pass backwards to the 



FIG. 229. LARYNGEAL AND TRACHEAL SKELETON OF UROPELES. A, Ntcturus 

 (Menobranchus) ; j3, Siren lacertina ; C, Amphiuma ; D, Salamandra maculosa. 



a, the cartilages (arytenoids) on either side of the glottis ; a', ridge for muscles ; 

 *, the representative of the cricoid cartilage ; ft, cartilages of the trachea 

 in Siren ; Kb, the more definite tracheal cartilaginous tracts in Amphiuma 

 and Salamandra ; X IV , fourth branchial arch, from which the dilator (d) of 

 the trachea and larynx arises ; co, constrictor of the larynx ; L, L', lungs. 



roots of the lungs (Fig. 230). Vocal cords are developed in the 

 Anura only, each being attached to the inner concave surface 

 of the corresponding arytenoid. 



Ca 



Sp 



C.I* 



FIG. 230. CARTILAGINOUS SKELETON OF THE LARYNGO-TRACHEAL CHAMBER OF 

 Rana esculenta. (A, from above ; B, from the side.) 



Ca, Ca, arytenoid cartilage ; C.I 1 to C.I 4 , cricoid cartilage ; Sp, process of the 

 latter ; P, plate-like broadening out of the ventral part of the cricoid ; SR, 

 glottis ; ***, three tooth-like prominences of the arytenoids. 



Reptiles. The larynx of Reptiles is supported by cartilaginous 

 elements comparable to those of Anura, there being two sets of 



