172 REP TIL IA. 



teus, in which it forms a cylindrical cavity, which is narrow supe- 

 riorly toward the glottidean fissure, and beneath the latter is con- 

 tinued through the intervention of two sacs into the lungs. Within 

 this rudimentary larynx are situated several strips of cartilage, cor- 

 responding to the pars aryt&noidea and laryngo-trachealis. In the 

 Tritons and Salamanders, where the sacs or rudimental indications 

 of the bronchi are absent, the laryngeal or vocal box, compressed 

 from before backward, is supported by a superior arytenoid, and 

 an inferior lateral or laryngo-tracheal cartilage. The structure is 

 similar in one family of Ichthyodea, comprising the Menopome, Am- 

 phiume and Axolotl, as also in Coecilia, where several tracheal rings 

 are already met with. 



Resembling more nearly the larynx of the higher animals, but 

 with diverse modifications, we come now to consider the structure 

 of the laryngeal cavity in the Anourous Batrachia ; a subject of 

 special interest from the differences which it presents in the two 

 sexes of these Amphibia. This latter circumstance is very strikingly 

 exemplified by its conditions in the males of the genus Pipa. The 

 aryt&noid cartilages are here of considerable size, triangular in form, 

 and articulate with the lateral or laryngo-tracheal cartilages situ- 

 ated beneath them, and here united into a single body ; this, which 

 corresponds to the thyroid cartilage, forms at the same time the up- 

 per part of the trachea, and diminishes greatly in size opposite to 

 the arytaenoid cartilages. The glottidean fissure is situated quite 

 close to the root of the tongue, and there are always found in this 

 situation, with but few exceptions, as in Pipa and Dactilethra, a pair 

 of vocal chords, that correspond to the ligamenta inferiora of the 

 Mammalia, and are attached before and behind to the arytaenoid 

 cartilages. Beneath the vocal chords are situated a pair of cavities 

 analogous to the ventricles of Morgagni. A pair also of inferior vocal 

 ligaments, narrower than the true ones, and formed by simple folds 

 of mucous membrane, frequently occur. 



In the Squamigerous Reptiles, the separation of the larynx from 

 the trachea is more distinctly shown. The arytaenoid and thyroid 

 cartilages in the Serpents are frequently blended together. In the 

 Crocodiles and Tortoises, and in many of the Sauria, the thyroid 

 cartilage is very developed, isolated from the rest, and being pro- 

 vided with special processes, resembles that in the larynx of Man. 

 Frequently there is developed from it in the direction upward a 

 fold of mucous membrane or a processus epiglotticus, which as in 

 the Chameleon, may be viewed as a rudiment of the laryngeal valve. 



