TABLE 3.--The Relationship of Length of Abdominal Scute to Plastral Length, and of Plastral Length to Length of Carapace, in 103 Specimens of _T. o. ornata_ Arranged in Five Groups According to Length of Carapace. The Relative Lengths of Abdominal Scute and Plastron are not Significantly Different in the Five Groups. The Plastron Tends to be Longer than the Carapace in Specimens of Adult or Nearly Adult Size. ===============+=========+===========================+================== | | Length of abdominal |Individuals having | | as a percentage of | plastron longer LENGTH | Number | length of plastron | than carapace OF CARAPACE | of | | |specimens|----------------+----------+------+----------- | |Mean ±[sigma]m | Extremes |Number|Percentage ---------------+---------+----------------+----------+------+----------- Less than | | | | | 50 mm. | 23 | 18.3±.498 |13.7-20.3 | 7 | 38.5 (Juveniles) | | | | | ---------------+---------+----------------+----------+------+----------- 50 to 69 mm. | 20 | 17.8±.303 |15.2-20.2 | 8 | 40.0 (Juveniles) | | | | | ---------------+---------+----------------+----------+------+----------- 70 to 100 mm. | 20 | 17.9±.445 |14.3-20.6 | 15 | 75.0 (Subadults) | | | | | ---------------+---------+----------------+----------+------+----------- More than | | | | | 100 mm. | 20 | 17.8±.236 |16.4-20.6 | 13 | 65.0 (Adult males) | | | | | ---------------+---------+----------------+----------+------+----------- More than | | | | | 100 mm. | 20 | 18.8±.510 |15.1-25.7 | 19 | 95.0 (Adult females)| | | | | ---------------+---------+----------------+----------+------+----------- The length of any growth-ring on the abdominal lamina can be used to determine the approximate length of the plastron at the time the growth-ring was formed. Actual and relative increases in length of the plastron can be determined in a like manner. For example, a seven-year-old juvenile (KU 3283) with a plastron 74.0 millimeters long had abdominal growth-rings (beginning with areola and ending with the actual length of the abdominal) 5.9, 7.8, 9.5, 10.7, 12.0, 12.5, 14.3, and 14.9 millimeters long. Using the [AB AB¹] proportion, [-- = -- ], where AB is the abdominal length, PL the [PL X ]