_Comparisons._--_T. s. spinifer_ can be distinguished from all other subspecies of _T. spinifer_ by the presence of large black ocelli (diameter 9-10 mm. on adult males, 2-3 mm. on hatchlings) in combination with only one dark marginal line. _T. s. spinifer_ resembles _asper_ in having ocelli or dots on the carapace but differs from _asper_ in having only one dark marginal line and larger ocelli. _T. s. spinifer_ differs from _hartwegi_ only in the large size of the ocelli. _T. s. spinifer_ resembles _hartwegi_ and _asper_ but differs from _pallidus_, _guadalupensis_ and _emoryi_ in having blackish spots and ocelli on the carapace and lacking whitish dots. _T. s. spinifer_ resembles _hartwegi_, _asper_, and _pallidus_ and differs from _guadalupensis_ and _emoryi_ in having conical or knoblike tubercles on the anterior edge of the carapace on large females. _T. s. spinifer_ differs from the subspecies _asper_, _guadalupensis_ and _emoryi_ in having a relatively narrower head, and from _emoryi_ in having a relatively wider carapace. _T. s. spinifer_ resembles _hartwegi_ and _asper_ but differs from the other subspecies in having the carapace widest at a plane approximately one-half way back on the carapace. The subspecies _spinifer_ and _hartwegi_ have longer snouts than _pallidus_, _guadalupensis_, and _emoryi_. _T. s. spinifer_ differs from _asper_ but resembles all the other subspecies in having a relatively longer plastron. _Remarks._--Lesueur's description of _Trionyx spiniferus_ (1827:258-261, Pl. 6) seems to be based mostly, if not entirely, on a large female (length of carapace, 13 inches), which was "Le plus grand des individus observes ..." (_op. cit._:258); an accompanying illustration depicting the dorsal surface of the bony carapace is unusual in lacking neurals (Pl. 6, E). Duméril and Bibron (1835:481) mentioned eight or nine additional specimens that Lesueur sent to the Museum of Natural History in Paris. Dr. Jean Guibé informed me under letter dated September 24, 1959, that a larger stuffed female, bearing catalog number 8808 is regarded as the holotype, and that there are seven additional specimens (1949, 4143, 8807, 8809-12) in the museum at Paris. All turtles were obtained by Lesueur from the Wabash River. To my knowledge no specimen that was available to Lesueur has been specifically designated as a type. Because the description seems to be based on one specimen, undoubtedly No. 8808, this specimen has been regarded as the holotype. However, Lesueur referred to several specimens and did not mention a type in the original description; consequently I prefer to regard No. 8808 as a lectotype.