Hooper (1953:8) and Ingles (1959:395) reported _O. melanotis_ as caught at the edges of cane fields.

=Oryzomys melanotis carrorum= Lawrence

1947. _Oryzomys rostratus carrorum_ Lawrence, Proc. New England Zool. Club, 24:101, May 29, type from Rancho Santa Ana, about 8 mi. SW Padilla, Rio Soto la Marina, Tamaulipas.

1959. _Oryzomys melanotis carrorum_, Hall and Kelson, The Mammals of North America, 2:560, March 21.

_Distribution in Tamaulipas._--Southeast part of state; known only from the type locality and the Sierra de Tamaulipas.

The original description of this subspecies was based on three specimens collected at Rancho Santa Ana. Specimens examined from the Sierra de Tamaulipas extended the known range 45 miles southeast of the type locality, and also extend the previously known alt.i.tudinal range of 300-350 feet elevation to 1200 feet.

Specimens examined correspond in color and measurements to those recorded by Lawrence (1947:102-103). Of 12 specimens studied, the tympanic bullae of six touch the surface of the table when the skull rests on the tips of the incisors and the occipital condyles. In the other six the bullae are 0.3 to 1.3 mm. above the table top. The mesopterygoid s.p.a.ce in the specimens examined are broad and U-shaped and not V-shaped as in the three specimens examined by Lawrence (_op.

cit._). Weight of six males was 52.5 (48-63) and of four females 44.7 (40-49) grams.

_Measurements._--Average and extreme measurements of six males are as follows: 255.3 (240-269); 135.7 (120-147); 135.7 (120-147); 30.4 (30-31); 21 (20-22); greatest length of skull, 31.6 (30.9-32.5); zygomatic breadth, 15.3 (14.7-16.1); interorbital constriction, 4.8 (4.5-5.1); breadth of skull, 31.6 (30.9-32.5); length of nasals, 12.9 (12.4-13.4); length of anterior palatine foramina, 5.5 (5.2-5.7); length of palatal bridge, 6.1 (5.8-6.4); length of maxillary tooth-row, 4.0 (3.9-4.1). The females average slightly smaller.

_Records of occurrence._--Specimens examined, 12 from Sierra de Tamaulipas, 10 mi. W, 2 mi. S Piedra, 1200 ft.

Additional record: Type locality (Lawrence, 1947:102).

=Oryzomys melanotis rostratus= Merriam

1901. _Oryzomys rostratus_ Merriam, Proc. Washington Acad.

Sci., 3:293. July 26, type from Metlatoyuca, Puebla.

1953. _Oryzomys melanotis rostratus_, Hooper, Occ. Papers Mus. Zool., Univ. Michigan, 544:8, March 25.

_Distribution in Tamaulipas._--Extreme southeastern part of state, in tropical area.

Ingles (1959:395) reported one specimen from two miles north of Ciudad Mante as _O. melanotis_; here it is referred to _O. m. rostratus_ on geographic grounds.

_Records of occurrence._--Specimens examined, 2: 2 km. W El Carrizo, 1; Rancho Pano Ayuctle, 25 mi. N El Mante and 3 km.

W Highway, 1.

Additional records: 2 mi. N Cd. Mante (Ingles, 1959:395); Altamira (Goldman, 1918:54).

=Oryzomys alfaroi huastecae= Dalquest

1951. _Oryzomys alfaroi huastecae_ Dalquest, Jour.

Washington Acad. Sci., 41:363, November 14, type from 10 km.

E Platanito, San Luis Potosi.

_Distribution in Tamaulipas._--Known only from Rancho del Cielo (Hooper, 1953:8).

=Oryzomys fulvescens=

Pygmy Rice Rat

The pygmy rice rat in Tamaulipas was collected in gra.s.s. Two kilometers west of El Carrizo in gra.s.s around a sugar cane field, traps, baited with sc.r.a.ps of deer meat, caught _Oryzomys fulvescens_, _Sigmodon hispidus_, _Peromyscus leucopus_ and _Liomys irroratus_. Seven kilometers north of Tampico, _O. fulvescens_ was taken along with _Peromyscus leucopus_, _Sigmodon hispidus_ and _Baiomys taylori_.

A female obtained on March 2, at Rancho Pano Ayuctle, had 4 embryos 16 mm. in crown-rump length.

=Oryzomys fulvescens fulvescens= (Saussure)

1860. _H[esperomys]. fulvescens_ Saussure, Revue et Mag.

Zool., Paris, ser. 2, 12:102, March, type from Veracruz; fixed by Merriam (Proc. Washington Acad. Sci., 3:295, July 26, 1901) at Orizaba.

1897. _Oryzomys fulvescens_, J. A. Allen and Chapman, Bull.

Amer. Mus. Nat. Hist., 9:204, June 16.

_Distribution in Tamaulipas._--Reported only from Rancho del Cielo (Goodwin, 1954:10).

=Oryzomys fulvescens engracie= Osgood

1945. _Oryzomys fulvescens engracie_ Osgood, Jour. Mamm., 26:300, November 14, type from Hacienda Santa Engracia (32 km. N), NW of Cd. Victoria, Tamaulipas.

_Distribution in Tamaulipas._--Central and southeast parts of state.

_Records of occurrence._--Specimens examined, 13: 2 km. W El Carrizo, 5; Rancho Pano Ayuctle, 25 mi. N, 3 km. W El Mante, 6; 10 km. N, 8 km. W El Encino, 1; 7 km. N Tampico, 1.

Additional record: Altamira (Osgood, 1945:300).

=Reithrodontomys megalotis hooperi= Goodwin

Western Harvest Mouse

1954. _Reithrodontomys megalotis hooperi_ Goodwin, Amer.

Mus. Novit., 1660:1, May 25, type from Rancho del Cielo, 5 mi. NW Gomez Farias, 3500 ft., Tamaulipas.

_Distribution in Tamaulipas._--Known only from type locality.

=Reithrodontomys fulvescens=

Fulvous Harvest Mouse

This is the most common species of _Reithrodontomys_ in Tamaulipas; it occurs in almost all parts of the state, from sea level to high up in the mountains and from the tropical forest to the desert plain.

The three subspecies in the state are _R. f. intermedias_ in the northern half, _R. f. griseoflavus_ in the high parts of the Sierra Madre Oriental, and _R. f. tropicalis_ in the southeast. The lines between these subspecies are difficult to establish because the zones of intergradation are broad. Characters for separating the three subspecies in Tamaulipas are listed by Hooper (1952).

=Reithrodontomys fulvescens griseoflavus= Merriam