Specimens of _T. spinifer_ in the lower Mississippi Valley are intergrades. Most individuals have small black dots on the carapace; some have small ocelli (TU 7216, 7501, 11912, 12123-24) interspersed with black dots (TU 5863), others have black dots confined to the edge of the carapace (TU 157, 4539, 7105), and still others have no pattern on the carapace (TU 7506, 13698.1, 10087.6). Two large males (TU 11580, 13025) have large ocelli (approximately five mm. in diameter) that have nearly black centers. In general, there is more dark pigmentation than farther north; some specimens have extensive pigmentation on the ventral surface of the carapace and soft parts of the body (TU 156, 5648). The dorsal surface of the limbs, especially the hind limbs, have a bold, black marbling and may be almost completely black (TU 5484, 5597). Many females, not exceeding plastral lengths of 7.0 centimeters, have a pale blotched pattern of lichenlike figures or have ill-defined black dots on the carapace (TU 10087, 13698.13, 13753.15). Localities of specimens of _T. spinifer_ occurring in the Mississippi River drainage in Mississippi are arbitrarily listed under the account of the subspecies _spinifer_, whereas those in Louisiana (excluding _pallidus_) are listed under the account of _hartwegi_. Neither Over (1943) nor Wheeler (1947:169) record _T. s. hartwegi_, respectively, from South Dakota or North Dakota; records from the Missouri River drainage in Montana suggest the occurrence of the species in that drainage in North and South Dakota. _Specimens examined._--Total, 392 as follows: ARKANSAS: _Clay_: UMMZ 70735 (2), 7 mi. S St. Francis. _Crawford_: USNM 95352, Lee Creek, 7 mi. NW Natural Dam. _Drew_: CNHM 40785. _Lafayette_: KU 2225-29, 2944 (one of three specimens bearing last catalog number), 2963 (one of three specimens bearing this catalog number), 2964 (one of two specimens bearing this catalog number), Lewisville (see remarks under the account of the subspecies _pallidus_). _Lawrence_: CNHM 8949; CNHM 12598-600, 12602-04, TU 5855, UI 2413, Imboden; UI 2412, Black River at Powhatan. _Marion_: TU 14591 (6), White River at Cotter. _Prairie_: KU 1867, 1869, 1879, 1949-51, 2280-83, 2285-91 (2 specimens bear catalog number 2287), 2307, 2761-62, 2666, 2826, 2842, 3346-47, White River at DeValls Bluff. _Pulaski_: UMMZ 96540, Little Rock. _Saline_: USNM 17823, Saline River at Benton. _Searcy_: UMMZ 92755, Little Red River, 1.5 mi. SE Leslie. _Yell_: TU 14565, Petit Jean Creek, 10 mi. N Casa. _County unknown_: CNHM 28566-67, Ouachita River.