Lungs Reptilian lungs 

Reptilian lungs are typically ventilated by a combination of expansion & contraction of the ribs via axial muscles & buccal pumping. Crocodilians also rely on the hepatic piston method, in which the liver is pulled back by a muscle anchored to the pubic bone , which in turn pulls the bottom of the lungs backward, expanding them. Turtles, which are unable to move their ribs, instead use their forelimbs & pectoral girdle to force air in & out of the lungs.

The lung of most reptiles has a single bronchus running down the centre, from which numerous branches reach out to individual pockets throughout the lungs. These pockets are similar to, but much larger & fewer in number than, mammalian alveoli, & give the lung a sponge-like texture. In tuataras, snakes, & some lizards, the lungs are simpler in structure, similar to that of typical amphibians.

Snakes & limbless lizards typically possess only the right lung as a major respiratory organ the left lung is greatly reduced, or even absent. Amphisbaenians, however, have the opposite arrangement, with a major left lung, & a reduced or absent right lung.