LARYNX 01'' REPTILES. 



527 



sending off lateral branches : it then abrnptly 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 Ijy numerous round apertures into the smaller 

 subdivisions forming the cellular structure of the lung.' 



§ 9 5. Larynx of Reptiles. — In perennibranchial and tailed 

 Batrucliia 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 02iens 

 into a small membranous cavity, usually kept patent by lateral 

 cartilages, from which the lungs diverge directly in Proteus, 

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

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

 either membranous or with feeble rudiments of cartilaginous rings. 



In tailless Batrachia the larynx is well developed, esjoecially 

 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 upjaer and lateral boundary of the 

 larynx, fig. 351, a: the ohordas 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 

 rimas 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- 

 ing in the mute Pipa. In Bomhinator igneus 

 and Hyla verrucosa the arytenoids are ob- 

 tuse-angled and nearly equilateral triangles. In Bufo cinereus 



350 



Tongue, larj-nx, and lungs, 



male Prog, Rrnin temporaria, 



cccxx. 



XX. vol. ii. p. 97, prep. no. 1118. 



