Ontogenetic variation in PL/HW, mean PL/HW of specimens having plastral lengths 7.0 centimeters or less, 4.15, and exceeding 7.0 centimeters, 5.32; ontogenetic variation in CL/CW, mean CL/CW of specimens having plastral lengths 8.5 centimeters or less, 1.10, and exceeding 8.5 centimeters, 1.14; mean CL/PCW, 2.12; mean HW/SL, 1.38 (including subspecies _guadalupensis_); mean CL/PL, 1.36. _Variation._--In 1953, I casually glanced at a hatchling softshell from the Calcasieu River drainage in the private collection of Mr. Wilfred T. Neill; the specimen was considered by Neill (1951:15) as "... an intergradient one (with the _hartwegi-spinifer_ population in the lower Mississippi drainage)." The hatchling does deviate from "typical" _pallidus_ in having darkish flecks posteriorly on the carapace. I have seen only one adult male (USNM 94457) from the Sabine River drainage (Orange County, Texas) that shows characteristics of _guadalupensis_ (white dots on carapace encircled with small black ocelli); another adult male (USNM 94456) from the same locality resembles _pallidus_. Those two USNM specimens were mentioned by Neill (1951:13) as indicating intergradation with "... the mixed _spinifera-hartwegi-asper_ populations of Louisiana." Two adult males (SM 2889, Pl. 40, bottom, left, and TCWC 471, Trinity River drainage) have blackish ocelli surrounding the white dots on the posterior part of the carapace; two large females (TU 14402, Pl. 40, bottom, right, plastral length, 17.5 cm., and TU 14417 plastral length, 21.3 cm., both from the Trinity River) have contrasting mottled and blotched patterns with white dots visible on the carapace. These turtles show alliance with _guadalupensis_. Some individuals from the Brazos River drainage have features suggesting those that are characteristic of _guadalupensis_. Hatchlings may have large white dots on the anterior half of the carapace (USNM 55601). Adult males may have dusky ocelli surrounding the white dots on the carapace (TU 14169, 14559.1, 14559.2). The whitish dots, rarely as large as two millimeters, are never so large as in _guadalupensis_ (three mm. in diameter), and are usually smaller anteriorly than posteriorly; TU 14169 has white dots approximately the same size (1.2 mm.) on the anterior half as on the posterior half of the carapace. The tubercles on adult males are equilateral or subconical, usually having sharp tips (TU 14348, 14559.1, 14559.2); the tubercles on large females are subconical, resembling the end of a bullet, and, in both sexes the tubercles are less conical than those on specimens of _pallidus_ from farther east.