The names, absolute synonyms, and geographic ranges of the two subspecies of _Sciurus aureogaster_ here recognized are as follows: SCIURUS AUREOGASTER AUREOGASTER F. Cuvier 1829. _Sciurus aureogaster_ F. Cuvier, Hist. Nat. Mammiferes, VI, livr. LIX, pl. with text. 1830. _Sciurus rafiventer_ Lichenstein, Abhandl. K. Akad. Wiss., Berlin, p. 116 (1827). 1831. _Sciurus leucogaster_ F. Cuvier, Suppl. d'Hist. Nat. Buffon, pp. 300, 301. 1831. _Sciurus hypopyrrhus_ Wagler, Oken's Isis, pp. 510, 511. 1841. _Sciurus mustelinus_ Audubon and Bachman, Proc. Acad. Nat. Sci. Philadelphia, pp. 100, 101. 1841. _Sciurus ferruginiventris_ Audubon and Bachman, Proc. Acad. Nat. Sci. Philadelphia, p. 101. 1845. _Sciurus ferrugineiventris_ Schinz, Synopsis Mamm., II, p. 14. 1855. _Sciurus hypoxanthus_ (Lichenstein MS) Geoffroy, Voyage de la Venus, Zool. (text), pp. 158, 159 (on labels of squirrels from Berlin Museum, _fide_ Nelson, Proc. Washington Acad. Sci., 1:38, May 9, 1899). 1855. _Sciurus chrysogaster_ Giebel, Saugethiere, p. 650. 1867. _Macroxus aureogaster_ Gray, Ann. and Mag. Nat. Hist., ser. 3, 20:423. 1867. _Sciurus hypopyrrhous_ Gray, Ann. and Mag. Nat. Hist, ser. 3, 20:424. 1867. _Macroxus morio_ Gray, Ann. and Mag. Nat. Hist., ser. 3, 20:424. 1867. _Macroxus maurus_ Gray, Ann. and Mag. Nat. Hist., ser. 3, 20:425. 1887. _Sciurus rufiventris?_ Rovirosa, La Naturaleza, 7:360 (1885-1886). 1897. _Sciurus leucops_ Allen, Bull. Amer. Mus. Nat. Hist., 9:198. 1899. _Sciurus aureogaster hypopyrrhus_ Nelson, Proc. Washington Acad. Sci., 1:42, May 9. _Range._--Eastern slope of Mexico from southern Tamaulipas southward to Tabasco and Chiapas. Marginal localities arranged clockwise beginning with the northernmost station of record are: _Tamaulipas_: Victoria; Altamira; down the coast to _Veracruz_: Coatzocoalcos; inland to _Tabasco_: Montecristo. _Chiapas_: Tumbala. _Oaxaca_: Mountains near Santo Domingo. _Veracruz_: Otatitlan; Orizaba; Jico; Jalapa. _Puebla_: Metlaltoyuca. _Hidalgo_: Sierra Encarnacion. _Queretaro_: Pinal de Amoles. _San Luis Potosi_: Valles. _Tamaulipas_: Forlon. Specimen No. 51383 Chicago Mus. Nat. Hist., labelled as from San Luis Potosi, in the State of the same name, does not represent, I suspect, a natural occurrence of the animal. Possibly the specimen was purchased there in the market, but was actually captured elsewhere. SCIURUS AUREOGASTER FRUMENTOR Nelson 1898. _Sciurus aureogaster frumentor_ Nelson, Proc. Biol. Soc. Washington, 12:154, June 3. _Range._--Higher elevations of the Cofre de Perote. Marginal localities, both in Veracruz, are: Above Las Vigas; Jico.