A male and female, both adults, from the same locality in the Sierra de Tamaulipas weighed, respectively, 3,150 grams and 4,836 grams. Three young from the same place weighed 2,250, 2,250, and 2,650 grams. _Records of occurrence._--Specimens examined, 7: Sierra de Tamaulipas, 10 mi. W, 2 mi. S Piedra, 1200 ft., 5; Rancho Pano Ayuctle, 25 mi. N El Mante, 3 km. W Pan-American Highway, 2200 ft., 1; 2 km. W El Carrizo, 1. Additional records: Sierra San Carlos (San José, El Mulato) (Dice, 1937:249); Soto la Marina (Goldman, 1942:81); Cd. Victoria (_ibid._); 10 mi. NE Zamorina (Hooper, 1953:3); 3 mi. NW Acuña (_ibid._); 19 km. SW Mante (Davis, 1944:381). =Potos flavus aztecus= Thomas Kinkajou 1902. _Potos flavus aztecus_ Thomas, Ann. Mag. Nat. Hist., ser. 7, 9:268, April, type from Atoyac, Veracruz. _Distribution in Tamaulipas._--Uncertain; one specimen was seen by Leopold (1959:437) near Acuña. =Mustela frenata= Long-tailed Weasel This species occurs in practically all of the state, but as in most other areas actual records are few; only two specimens, both males, have been examined. One was taken at Jaumave, in a steel-trap baited with fresh egg. It weighed 325 grams. The other was taken in the vicinity of Altamira and weighed 434 grams. Two subspecies have been reported from Tamaulipas; _Mustela frenata frenata_ that occurs in the central and northern parts of the state and _M. f. tropicalis_ that occurs in the tropical area in the southern part of the state. =Mustela frenata frenata= Lichtenstein 1831. _Mustela frenata_ Lichtenstein, Darstellung neuer oder wenig bekannter Säugethiere ..., pl. 42 and corresponding text, unpaged, type from Ciudad México, México. 1877. _Putorius mexicanus_ Coues, Fur-bearing animals, U. S. Geol. Surv. Territories, Misc. Publ., 8:42, a _nomen nudum_ [cited by Coues in synonymy as "_Putorius mexicanus_, Berlandier, MMS. ic. ined. 4 (Tamaulipas and Matamoras)"]. _Distribution in Tamaulipas._--Central and northern parts of state.