154 BULLETIN 18 7, UNITED STATES NATIONAL MUSEUM 



livr. 13, 1893, p. 740, pi. 53, fig. 3 (head scales).— Dunn, Copeia, 1931, No. 4, 

 p. 163. — Taylcb, Herpetologica, vol. 2, 1942, pp. 75-77. — Smith, Pioc. U. S. 

 Nat. Mus., vol. 93, 1943, pp. 394-396. 



Type. — Original lost (skull only said to be extant). A neotype in 

 Mus. Alfredo Duges, Univ. Guanajuato, Mexico. 



Type locality. — Guadalajara, Jalisco. 



Range. — Jalisco, Guanajuato, and Morelos (known from six locali- 

 ties: Guadalajara, La Cumbre de los Arrastraclos, and Magdalena, 

 Jalisco; Tupataro and Guanajuato, Guanajuato; and Yautepec, 

 Morelos) . 



Genus NATRIX Laurenti 



Natrix Laukenti, Specimen medicum exhibens synopsin reptilium . . ., 1768, p. 

 73.— Clay, Copeia, 1938, No. 4, pp. 173-182 (keys and brief diagnoses for 

 American species). 



Genotype. — Natrix vulgaris Laurenti ( =" Coluber natrix Linnaeus). 



Range. — Africa, Europe, Asia, Malay Archipelago, northern Aus- 

 tralia and adjacent islands; in the Western Hemisphere, southeastern 

 Canada, all of eastern and central United States west to Kansas, and 

 extreme southern portion of the western states; in Mexico, the tip 

 of Baja California, a western area from Durango to Guerrero, and an 

 eastern area from Texas to Guatemala ; Cuba. 



Species. — Twenty-one species and subspecies in the Americas, of 

 which only four occur in Mexico ; about 75 in the Eastern Hemisphere. 



KEY TO MEXICAN FORMS OF NATRIX 



1. Pattern of large dorsal blotches ; lateral blotches reach ven- 



trals erythrogaster transversa 



Pattern of small or indistinct dorsal blotches ; lateral blotches reach 

 ventrals or not 2 



2. Scale rows 19 to 23 ; no large lateral spots ; belly immaculate valida 



Scale rows 25 to 31 ; large lateral spots ; belly immaculate or not 3 



3. Ventrals strongly marked with semilunar dark spots ; dorsal color 



pattern usually distinct rhombifera rhombifera 



Ventrals nearly or quite immaculate ; dorsal pattern obscure 



rhombifera blanchardi 



NATRIX ERYTHROGASTER TRANSVERSA (Hallowell) 



Tropidonotus transversus Hallowell, Proc. Acad. Nat. Sci. Philadelphia, vol. 6, 



1852, p. 177. 

 Natrix erythrogaster transversa Taylor, Univ. Kansas Sci. Bull., vol. 19, 1929 



(1930), p. 58.— Parker, Journ. Tennessee Acad. Sci., vol. 12, 1937, p. 76, tig. 9A. 

 Nerodia Couchii Kennicott, Proc. Acad. Nat. Sci. Philadelphia, vol. 12, 1860, 



p. 335 (San Diego and Santa Catarina, Nuevo Leon; cotypes, U.S.N.M. Nos. 



1314,1319). 



Type.— Acad. Nat. Sci. Phila. No. 5044. 



Type locality. — Boundary of Creek Nation, near the banks of the 

 Arkansas and its tributaries. 



