Prmted in Great Britain THE MECHANISM OF LUNG VENTILATION IN THE TORTOISE TESTUDO GRAECA LINNE

Air-breathing vertebrates use at least two fundamentally distinct gas-pumping mechanisms. In the 'mammalian ' pattern the animal reduces the lung pressure below atmospheric; inflow thus occurs as a result of suction through a completely open channel. In the 'frog ' pattern, however, air does not pass directly into the lungs whic