Many characters of Trionyx ferox that are lacking in other North American forms are shared with some Asiatic softshells, such as the large size, longitudinal rows of tubercles that resemble ridges on the carapace, and the marginal ridge. It is thought that, of the living softshells in North America, ferox is more closely allied to Old World forms of the genus than to muticus or spinifer.

Carr (1940:107) recorded ferox from Okaloosa County, Florida, in the western end of the panhandle, whereas Crenshaw and Hopkins (1955:16) list the known westward extent of range as Leon and Wakulla counties. AMNH 6933 from west of the Apalachicola drainage in Washington County, Florida, tends to substantiate Carr's record, which is not included on the distribution map.

Specimens examined.—Total 144, as follows: Florida: Alachua: UMMZ 64178, 100969; USNM 10545, 10704, "near" Gainesville; UMMZ 56599, Levy Lake. Brevard: AMNH 12878, Canaveral. Broward: UMMZ 109441, Hugh Taylor Birch State Park; USNM 109548, 22 mi. WNW, 6 mi. SSE Fort Lauderdale. Collier: USNM 86828, Tamiami Trail, "near" Birdon. Dade: AMNH 50936, UMMZ 10183, 110981, Miami; USNM 84079, 86942, 15 mi. from (west) Miami, Tamiami Trail; UMMZ 111371, 19 mi. W, 1.3 mi. S Miami; UI 28984, 35 mi. W. (Miami) Tamiami Trail; AMNH 69932-33, UMMZ 101582, 101584, 104024, 40-45 mi. W Miami, Tamiami Trail. Glades: UMMZ 100836, mouth of Kissimmee River. Hendry: UMMZ 106302, 10.2 mi. SE Devil's Garden; UMMZ 106303-04, 106321-22, 30 mi. S Clewiston, near Devil's Garden. Hernando: TU 13624, 0.5 mi. S Citrus Co. line on US Hwy. 19. Highland: AMNH 65537, 71618, Archbold Biol. Stat., Lake Placid; AMNH 65622, Hicoria. Hillsborough: TU 13960, Hillsborough River, ca. 20 mi. NE Tampa; USNM 51184, Tampa; USNM 71156, Plant City. Indian River: USNM 55316, Vero Beach; USNM 59318, Sebastian. Lake: UMMZ 36072, USNM 20189, 029210, 029339, 38123, Eustis; UMMZ 76754-56, Lake Griffin. Lee: UMMZ 102276, 14 mi. SE Punta Gorda. Leon: CNHM 33701, USNM 95767, Lake Iamonia; USNM 103736, Silver Lake. Marion: AMNH 8294-95, UMMZ 95613 (4), USNM 52476-83, 100902-04, Eureka; AMNH 63642, near Salt Springs. Martin: TNHC 1292, 8.4 mi. N Port Mayaca. Okeechobee: AMNH 57379-84, Lake Okeechobee; AMNH 5931-32, Kissimmee Prairie. Orange: USNM 51421, 56805, Orlando; KU 16528. Osceola: USNM 029448, 029450-64, 029467-68, 029470, 029474-75, Kissimmee. Palm Beach: UMMZ 54101, Palm Beach; USNM 73199, Delray Beach. Pinellas: USNM 51417-20, St. Petersburg. Polk: AMNH 25543, Lakeland; UMMZ 112380, 6.7 mi. S Lake Wales; USNM 60496, 60532, 60534, 61083-87, Auburndale. Putnam: USNM 4373, 7651, Palatka; USNM 26035, ponds "near" Welaka. Sarasota: USNM 61352, Lake Myakka. Sumpter: UMMZ 71791, Bushnell. Volusia: UMMZ 100673, Lake Helen. Washington: AMNH 6933, Washington. County unknown: AMNH 4758; USNM 8899, St. John's River: USNM 59727-28, Lake Okeechobee, "near" mouth Taylor's Creek; USNM 84080.

Georgia: Baker: SM 2083, USNM 029619, 38980-81, 70398, Mimsville. [486] Berrien: USNM 62217, Banks Mill Pond. Charlton: AMNH 69934, Okefinokee Swamp, SW Billy's Island; UMMZ 90010, east edge Okefinokee Swamp; USNM 84603, Okefinokee Swamp, Chesser's Island. Irwin: USNM 56804. Lowndes: UMMZ 67706, 10 mi. S Valdosta. McIntosh: USNM 19621, Darien.

South Carolina: Charleston: USNM 9670, Charleston.

No Data: AMNH 22750; USNM 71608-09.

Records in the literature.—Florida: Alachua: 10 mi. ENE Gainesville (Schwartz, 1956:18). Brevard: Merritt Island (Neill, 1958:6). Broward: Fort Lauderdale (Schwartz, op. cit.:19). Charlotte: (Carr, 1940:107). Clay: Green Cove Springs (Brimley, 1910:18); St. John's River (Crenshaw and Hopkins, 1955:21); Doctor's Inlet (Schwartz, op. cit.:18). Collier: Royal Palm Hammock (Crenshaw and Hopkins, op. cit.:20); 11.2 mi. E Monroe Station (Schwartz, op. cit.: 19). Columbia: (Carr, loc. cit.). Dade: Paradise Key (Schwartz, loc. cit.); Homestead (eggs, Stejneger, 1944:43). Duval: 4-10 mi. S Jacksonville (Deckert, 1918:31). Glades: ca. 8 mi. SW Okeechobee State Park. Lake: Alexander Springs (Schwartz, op. cit.:18). Lee: 18 mi. S Fort Myers (Conant, 1930:63); 6 mi. SE Fort Myers (Hamilton, 1947:209). Levy: Gulf Hammock (Schwartz, loc. cit.); Brownson (Stejneger, op. cit.:42). Monroe and Okaloosa (Carr, loc. cit.). Okeechobee: 6 mi. E Kissimmee River; state hwy. 78 "near" Okeechobee-Glades co. line. Palm Beach: SW part of Lake Okeechobee, near Clewiston; Milton Island Cove (Schwartz, loc. cit.). Pasco: mouth Pithlachascotee River (Neill, op. cit.:26). Pinellas: Belleair (Brimley, loc. cit.); Seminole (Conant, loc. cit.); 5 mi. E Clearwater (Schwartz, op. cit.:19); Gulf Port (Stejneger, op. cit.:43). Polk: Lake Shipp, near Winter Haven (Telford, 1952:185). Sarasota: 15 mi. E Sarasota (Conant, loc. cit.); Venice (Conant, op. cit.:61). Taylor: "near" Foley. Wakulla: "near" Crawfordville (Crenshaw and Hopkins, op. cit.:15).

Georgia: Baker: 5 mi. NW Newton, 5 mi. W Newton, 4 mi. N Newton. Ben Hill: 6 mi. E Fitzgerald (Crenshaw and Hopkins, 1955:15). Bulloch: 14 mi. SE Statesboro (Schwartz, 1956:19). Decatur: "near" Bainbridge (Crenshaw and Hopkins, loc. cit.). Emanuel: "near" Midville. Evans: 8 mi. NE Manassas, Tattnall County. Ware: Laura Walker State Park (Schwartz, loc. cit.). Wilcox: 3 mi. SE Forest Glen (Crenshaw and Hopkins, op. cit.:19).

South Carolina: Beaufort: 7 mi. NE Gardens Corner (Schwartz, 1956:19). Chatham: Savannah River at Savannah (Schwartz, op. cit.:8-9). Colleton: 5 mi. from Whitehall, Combahee River (Schwartz, op. cit.:19).

Trionyx spinifer Lesueur
Spiny Softshell