Fig. 8. Still frames from an X-ray video recording of lung ventilation at rest in Terrapene carolina (individual 03). Simultaneous pneumotachographic airflow measurements were also recorded and synchronized with the X-ray video (Fig. 9). The lungs appear as a large light area in the middle of the body, and the pneumotach mask appears dark in this radio-positive lateral view. A small metal marker (arrow) has been glued to the skin of the inguinal flank just superficial to the oblique abdominis (OA) and transverse abdominis (TA) muscles. The upper frame shows the position of the metal marker when the animal has fully inflated lungs. The lower frame shows the metal marker at the end of exhalation. X-ray video clips with simultaneous pneumotachographic airflow recordings of Terrapene carolina breathing at rest and during locomotion can be viewed on line as part of this article (http://jeb.biologists.org/).