One hatchling (No. 1), when its temperature dropped below one degree, fully extended all four limbs and the body was elevated and only the anterior edge of the plastron was in contact with the confining glass dish. Raising the body from an uncomfortably cold or hot substrate is a well known phenomenon in many lizards and in crocodilians, but to my knowledge has not been reported for turtles. TABLE 5.--Average Rate of Change in Temperature (Expressed in Degrees per minute) for four Groups of Turtles Subjected to Temperature of Zero Degrees and then Allowed to Warm at 27 Degrees (Centigrade). ==================+========+=========+============= | | Cooling | Warming GROUP | Number | phase | phase | | | (to 25°) ------------------+--------+---------+------------- Hatchlings | 2 | .282 | .310 | | | Juveniles | 2 | .264 | .180 | | | Adult [Male] | 2 | .122 | .152 | | | Adult [Female] | 3 | .119 | .130[B] | | | Adult (all) | 5 | .120 | .138 ------------------+--------+---------+------------- [B] None of the females reached a temperature of 25° before the experiment was terminated. [Illustration: FIG. 23. Changes in temperature of the body of four juvenal (nos. 1 to 4) and five adult individuals of _T. o. ornata_ (nos. 5 to 9) exposed to a constant air temperature of zero degrees Centigrade for periods of 100 and 200 minutes, respectively. The vertical arrows indicate when the turtles were removed to an air temperature of 27 degrees. Sizes and weights of the turtles used are given in the text. Turtle number nine, a female, was killed by means of chloroform before experiment began. Rate of change in temperature in specimens was inversely proportional to size. All turtles survived the experiment.]