_Records of occurrence._--Specimens examined, 9: 36 km. N, 10 km. W Cd. Victoria, 1; Jaumave, 2400 ft., 5; Rancho Pano Ayuctle, 25 mi. N, 3 km. W El Mante, 2; 70 km. S Cd. Victoria (by highway) and 6 km. W of Highway, 1. Additional records: Río Corana (Lawrence, 1947:103); Pano Ayuctle (Hooper, 1953:8). =Oryzomys melanotis= Black-eared Rice Rat _Oryzomys melanotis_ occurs in Tamaulipas from Soto la Marina southward. Two subspecies are recorded: _O. m. carrorum_ in the north and _O. m. rostratus_ in the tropical area from Rancho Pano Ayuctle to Altamira. Specimens from the Sierra de Tamaulipas were trapped along a stream, edged with trees, bushes and rocks; at Rancho Pano Ayuctle the animals were in grass between banana groves. The specimen from 70 kilometers south of Ciudad Victoria was taken in tall grass near a field of sugar cane in a line of traps that yielded also _Peromyscus leucopus_, _Sigmodon hispidus_, _Liomys irroratus_, and _Oryzomys fulvescens_. 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, Río 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 altitudinal 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 space 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.