[Illustration: PLATE 31 _Trionyx ferox_, juveniles. _Top_--UMMZ 76755 (× 1) dorsal and ventral views; Lake Griffin, Lake County, Florida. _Bottom_--TU 13960 (× 3/4), dorsal and ventral views; Hillsborough River, _ca._ 20 mi. NE Tampa, Hillsborough County, Florida.] [Illustration: PLATE 32 _Top_--_Trionyx ferox_, female, UMMZ 90010 (× 2/9); east edge Okefinokee Swamp, Charlton County, Georgia. _Bottom_--Left, _Trionyx ferox_, adult male, UMMZ 102276 (× 1/5), 14 mi. SE Punta Gorda, Lee County, Florida; right, _Trionyx sinensis_, female, KU 39417 (× 3/10), 5 mi. ESE Seoul, Korea. All dorsal views; note resemblance of two species in having longitudinal ridging and marginal ridge of carapace.] [Illustration: PLATE 33 _Trionyx spinifer spinifer_, juveniles, dorsal views. _Top_--UMMZ 74518 (× 1-2/5); Portage Lake, Washtenaw County, Michigan. _Bottom_--TU 16132 (× 1-1/5); Sevierville, Sevier County, Tennessee.] [Illustration: PLATE 34 _Trionyx spinifer spinifer_, dorsal views. _Top_--Adult male, UMMZ 54401 (× 3/7), Portage Lake, Livingston County, Michigan. _Bottom_--Female, UMMZ 81699 (× 2/7), Ottawa County, Michigan.] [Illustration: PLATE 35 _Trionyx spinifer hartwegi_, dorsal views. _Top_--Juveniles; left, KU 40210 (× 9/10), 12-1/2 mi. S, 1-1/4 mi. W Meade, Meade County, Kansas; right, KU 16531 (× 1), Smoky Hill River, 3 mi. SW Elkader, Logan County, Kansas. _Bottom_--Adult Males; left, KU 18385 (× 2/5), Arrington, Comanche County, Kansas; right, KU 3758 (× 3/10), Little Salt Marsh, Stafford County, Kansas.] [Illustration: PLATE 36 _Trionyx spinifer hartwegi._ _Top_--Juveniles; left, TU 13885, dorsal view (× 3/4), Little Vian Creek, 1 mi. E Vian, Sequoyah County, Oklahoma; right, KU 3732, ventral view (× 5/7), Independence, Montgomery County, Kansas. _Bottom_--Adult female, TTC 719, dorsal view (× 2/7), 10 mi. S, 2 mi. W Gruver, Hansford County, Texas.] [Illustration: PLATE 37 _Trionyx spinifer asper_, juveniles, dorsal views. _Top_--Left, male, KU 50839 (× 9/10), Flint River, 1-1/2 mi. S Bainbridge, Decatur County, Georgia; right, female, TU 15661 (× 9/10), Blackwater River, 4.3 mi. NW Baker, Okaloosa County, Florida. _Bottom_--Left, male, TU 13623 (× 7/9), Yellow River, 3.1 mi. W Hammond, Tangipahoa Parish, Louisiana; right, female, TU 14362 (× 4/5), Hobolochito Creek, 1 mi. N Picayune, Pearl River County, Mississippi.] [Illustration: PLATE 38