LARYNX OF REPTILES. 



527 



sending off lateral branches : it then abruptly terminates in a 

 dilated elongated passage, similar to those in which the side- 

 branches open. These passages correspond with the primary 

 divisions of the pulmonary cavity in the . Turtle, and the air 

 passes from them by numerous round apertures into the smaller 

 subdivisions forming the cellular structure of the luno;. 1 



o 



93. Larynx of Reptiles. In perennibranchial and tailed 

 Batrachia the glottis is a simple longitudinal fissure, fig. 346, , 

 in the middle of the ventral walls of the pharynx, each side of 

 which is commonly strengthened by a slender portion of fibro- 

 cartilage (Amphiuma), or so divided as to represent an ( arytenoid ' 

 and a ' laryngo-tracheal ' cartilage (Proteus). The slit opens 

 into a small membranous cavity, usually kept patent by lateral 

 cartilages, from which the lungs diverge directly in Proteus, 

 Ampliiuma, and Triton, and with a short trachea intervening in 

 Siren, Axolotes, Menopoma, and Salamandra, the trachea being 

 either membranous or with feeble rudiments of cartilaginous rino-s. 



O C5 



In tailless Batrachia the larynx is well developed, especially 

 in the males. There is, in most, an annular thyrocricoid cartilage, 

 which supports in all a pair of large arytenoids, of a triangular 

 shape, the apex forming the upper and lateral boundary of the 

 larynx, fig. 351, a : the chords vocales 

 stretch transversely from one end of the 

 base to the other, and are wanting only in 

 Pipa and Dactylethra. Above and below 

 the vocal chords, fig. 350, c, there is a 

 mucous pouch ; and between the chords 

 there is, in some species, a cartilage. The 

 muscles are a ( dilator ' and a ' constrictor 

 rima3 glottidis,' and a ' compressor glottidis,' 

 arising from the cerato-branchials, fig. 74, 

 p. 91, and inserted into the posterior angle 

 of the arytenoid : by bending this angle 

 outward, it stretches the vocal chords, and, 

 both muscles acting, they compress the 

 larynx. This is an influential muscle in 

 regard to the voice or croak, and varies with 

 its quality in different species ; it is want- 

 ins; in the mute Pipa. In Bombinator iqneus T T g ^ ie ' lai J nx ' and lungs ' 



-* y male Frog, Sana temporaria. 



and Hyla verrucosa the arytenoids are ob- cccxx - 



tuse-angled and nearly equilateral triangles. In Bufo cinereus 



1 xx. vol. ii. p. 97, prep. no. 1118. 



350 



-c 



