CHECKLIST OF REPTILES OF MEXICO 21 



CHELYDRA SERPENTINA (Linnaeus) 



Testudo serpentina Linnaeus, Systema naturae, ed. 10, vol. 1, 1758, p. 199. 

 Chelydra serpentina, Schweigger, Konigsberg. Arch. Naturw. Math., vol. 1, 

 1812, p. 293.— Cahn, Illinois Biol. Monogr., vol. 16, 1937, pp. 34-45, pis. 3-4. 



Type . — Unknown . 



Type locality. — "Warmer region," here restricted to New Orleans, 

 La. 



Range. — North America east of the Rocky Mountains; in Mexico, 

 Atlantic slopes south to the Yucatan Peninsula; recorded only from 

 the states of Veracruz and Campeche. 



Family KINOSTERNIDAE Agassiz 



Cinosternidae Agassiz, Contributions to the natural history of the United States, 

 vol. 1, 1857, p. 347. 



Genera. — Three. 



Range. — North America, south to northern South America. 



KEY TO GENERA OF KINOSTERNIDAE 



1. Plastron very small, cruciform, with 7-9 scutes; bridge narrow, its length 



(parallel to body axis) exceeded by its width; inframarginals little longer 



than broad 2 



Plastron larger, not cruciform, with 10 or 11 scutes; bridge broader, its length 

 much exceeding its width; inframarginals about three times as long as broad, 

 or longer Kinostemon (p. 21) 



2. A ligament between inframarginals and plastron Claudius (p. 26) 



A suture between inframarginals and plastron Staurotj^pus (p. 27) 



Genus KINOSTERNON Spix 



Kinosternon Spix, Ranae et testudinis brasiliensis species novae, 1825, p. 17. 

 Swanka Gray, Catalogue of the tortoises . . ., 1844, p. 32 (type, Kinosternon 



scorpioides Gray). 

 Platythyra Agassiz, Contributions to the natural history of the United States, 



vol. 1, 1857, p. 430, pi. 5, figs. 12-15 (type, Platythyra flavescens Agassiz). 

 Thyrosternum Kqkbbiz, op. cit., p. 429 (type, Kinosternum integrum LeConte). 



Genotype. — Kinosternon longicaudatum Spix=i^. scorpioides Lin- 

 naeus. 



Range. — United States, except the northwestern quarter, south to 

 northern South America. 



Species. — About 22 species and subspecies, 12 of which are known to 

 occur in Mexico. 



KEY TO MEXICAN SPECIES OF KINOSTERNON 



1. Plastron rounded behind, not incised or indented; stridulation organs 

 (on concealed surfaces of shank and thigh) in males poorly developed 

 or absent; plastron large, completely closing shell in adults 2 



