ORGANIZATIONOFREPTILES. 23 



than in the Mammaha and Birds; many can hve a long time without respiration; 

 it can be suspended even for months, and yet the hfe of the animal be preserved. 

 Toads can hve for years enclosed in plaister of Paris* or other hard bodies: 

 Belzoni, in excavating a ruin, found a Toad imbedded in a stone, and from the 

 position of the stone, he believed the animal must have been there more than a 

 thousand years. These singular phenomena would seem to indicate that the lungs 

 are not the sole organs capable of producing a change in the circulating fluids of 

 Reptiles. In Toads, Frogs, and Salamanders, the skin evidently at times performs 

 this office, making a kind of external or cutaneous respiration, similar to that 

 performed by the leaves of plants. The Salamanders breathe by lungs, and yet 

 they may be kept alive in running water for more than a month; here the change 

 of their circulating fluids must take place on the skin, and the same is probably 

 true with respect to Reptiles confined for a long time in sohd bodies, where the 

 air cannot penetrate to the lungs. It seems probable, from the interesting expe- 

 riments of Edwards,t that their existence is owing to the porosity of the substances 

 in which they are enclosed, allowing air or moisture to be brought in contact with 

 the surface of their bodies. The lungs are placed in the same common cavity 

 with the digestive organs; as there is never a distinct septum or diaphragm between 

 the thoracic and abdominal cavities. In the Chelonia, however, there is a muscle 

 that may be useful in respiration;^ I have found this well developed in the Emys 

 serrata, consisting of two lateral portions descending from the vertebral column and 

 inferior surface of the shell, and nearly surrounding the abdominal contents. The 

 lungs differ in the various tribes, but are of large proportionate size in all Reptiles. 

 In the Chelonia, they are situated above the other viscera, are very extensive, 

 reaching almost to the pelvis, and are capable of containing a great quantity of 

 air. In the Saurian animals, the lungs are similar to those of the Chelonia, but 

 in general they do not extend so far back — forming two sacs, varying in size, and 



* Herrissant enclosed three Toads in small boxes, and covered them with plaister; at the 

 end of eighteen months two were found alive and active. 



t De I'Influence des Agens Physiques, &c. Paris, 1824, p. 15. 

 t Meckel. Vergleich. Anat. Drit. Theil., p. 128. 



