_Remarks._--This immature male is paler than specimens of _O. r. rostratus_ from the state of Veracruz. This locality extends the known range of this species northward a distance of approximately 100 miles. Previously it had been recorded from only as far north as Alta Mira, Tamaulipas (Goldman, N. Amer. Fauna, 43:54, September 23, 1918). This specimen was trapped on February 16 in a rodent runway in dense grass in a fallow cane field. ~Oryzomys fulvescens engraciae~ Osgood Fulvous Rice Rat _Oryzomys fulvescens engraciae_ Osgood, Jour. Mamm., 26:300, November 14, 1945. (Type from Hacienda Santa Engracia, northwest of Ciudad Victoria, Tamaulipas, Mexico.) _Specimens examined_, 5 from 70 km. [by highway] S Ciudad Victoria and 2 km. E El Carrizo. _Remarks._--These specimens are referred to _O. f. engraciae_ on the basis of their pale color and narrow interorbital space. They were taken in runways in dense grass in fallow cane fields. ~Sigmodon hispidus toltecus~ (Saussure) Hispid Cotton Rat [_Hesperomys_] _toltecus_ Saussure, Revue et magasin de zoologie, _ser._ 2, 12:98, 1860. (Type from mountains of Veracruz, Mexico.) _Sigmodon hispidus toltecus_ Bailey, Proc. Biol. Soc. Washington, 15:110, June 2, 1902. _Specimens examined_, 23 as follows: 36 km. N and 10 km. W Ciudad Victoria, 1 km. E El Barretal, on Rio Purificacion, 1; 70 km. [by highway] S Ciudad Victoria and 2 km. W El Carrizo, 22. _Remarks._--Among named kinds of _Sigmodon_ this series most closely approaches _S. h. toltecus_ to the southward. The specimens are slightly lighter in color of the upper parts than are examples of this same subspecies from 8 km. NW of Potrero, Veracruz, but in other ways are similar. The single specimen from 36 km. N and 10 km. W Ciudad Victoria is a skull only, but seems closest to _S. h. toltecus_. As is often the case with collections of _Sigmodon_, this series contains mostly immatures. Cotton rats were found abundantly in cultivated areas. Local farmers stated that these rats were destructive to sugar cane by girdling the stems one and one-half inches above the ground. ~Neotoma micropus micropus~ Baird Baird Wood Rat _Neotoma micropus_ Baird, Proc. Acad. Nat. Sci. Philadelphia, p. 333, April, 1855. (Type from Charco Escondido, Tamaulipas, Mexico.) _Specimens examined_, 2 from 7 km. S and 2 km. W San Fernando. ~Neotoma angustapalata~ new species Tamaulipan Wood Rat _Type._--Male, subadult, skin and skull; No. 36976, Univ. Kansas Mus. Nat. Hist.; 70 km. [by highway] S Ciudad Victoria and 6 km. W of the [Pan-American] highway [at El Carrizo], Tamaulipas, Mexico; 14 January 1950; obtained by William J. Schaldach, Jr., original no. 578. _Range._--Known only from the type locality; probably found in other localities along the humid, east face of the Sierra Madre Oriental in Tamaulipas.