170 REPTILIA. 



tary larynx is continued directly into the membranous bronchi. 

 In the Salamanders a short membranous trachea exists, and in some 

 genera of Batrachia, as in Pipa, more or less perfect cartilaginous 

 leaflets and rings appear upon it. In the Ophidia also, as in Colu- 

 ber and Vipera, the trachea is often membranous at its commence- 

 ment, but provided further down with cartilaginous rings, which are 

 frequently osseous, e. g., in Crotalus and Python, where their num- 

 ber is very considerable, amounting to 300 rings and upward. The 

 rings are continued also over the single, or, where two lungs are 

 present, double bronchi. In the Sauria, the trachea varies in length, 

 being short with only 20 30 rings in the Chameleon, while in the 

 Crocodile upward of 80 occur. In the Chelonia, as in Testudo 

 graeca, the trachea is divided deeply and higher up, and is furnished 

 with strongly developed rings, which are continued throughout the 

 bronchi into the lungs. 



The Lungs exhibit remarkable diversities of form and structure. 

 Thus, in the Ichthyodea, as in the Proteus, the lungs form a pair 

 of very long narrow tubes which terminate inferiorly in a slightly- 

 expanded pyriform bladder. In the Triton they present the appear- 

 ance of elongated sacs, of tolerably uniform width throughout, and 

 terminating in a point, while in the Frogs they are much shorter 

 and broader. When the lungs have been fully expanded, they ex- 

 tend through the greater part of the abdominal cavity. In many 

 Sauria the lungs present similar characters, and are both of equal 

 size, e. g., Scincus. In the Apodal Sauria, as Anguis, Pseudopus, and 

 also in Chirotes, only one lung, and that usually the right, is pres- 

 ent, but in those Sauria with very short or only a single pair of feet, 

 as Zeps and Bipes, the left also exists, but is one third or more short- 

 er than that of the right side. In the Ophidia, as Boa and Python, 

 the length of the left lung is generally less by a third or half than 

 that of the opposite side, but in Coluber, Crotalus, and others, it is 

 much smaller, and quite rudimentary, appearing as an almost obliter- 

 ated appendage. The genera Ccecilia and Amphisbo3na appear on 

 the contrary to have the left pulmonary organ developed, and the 

 right shortened, this arrangement probably varying according to 

 the species. In the Viper and other Serpents there is only a single 

 lung, which on that account is always very long. The lungs are 

 flat and short in the Crocodile, but largest and most perfectly form- 

 ed in the Chelonia, where they extend beneath the carapace as far 

 as the pelvis. Here and there, as in Polychrus and Gecko, and es- 



