2. The subgenera _Eutamias_ and _Neotamias_ are valid, for, _Eutamias sibiricus_ differs from all the species of the subgenus _Neotamias_ to a greater degree than these species differ from one another. 3. The genera _Eutamias_ and _Tamias_ probably evolved from two distinct lines of sciurids; one line (_Eutamias_) is represented by the tribe Callosciurini, and the other (_Tamias_) by the tribe Marmotini. LITERATURE CITED CATESBY, M. 1743. The natural history of Carolina, Florida, and the Bahama Islands, etc., 2:i-xliv, 1-20, 1-100. ELLERMAN, J. R. 1940. The families and genera of living rodents. British Mus. (Nat. Hist.), Vol. 1, pp. xxvi + 689, 189 figs., June 8. ELLERMAN, J. R., and T. C. S. MORRISON-SCOTT. 1951. Checklist of Palearctic and Indian mammals. British Mus. (Nat. Hist.), pp. 1-810, 1 map, November 30. GMELIN, J. F. 1788. Systema Naturae. 1:1-500. HOWELL, A. H. 1929. Revision of the American chipmunks (genera _Tamias_ and _Eutamias_). N. Amer. Fauna 52:1-157, 10 pls., 9 maps, November 30. ILLIGER, J. K. W. 1811. Prodromus systematis mammalium et avium additis terminis zoographicis utriuque classis, pp. xviii + 302, C. Salfeld. LAXMANN, M. E. 1769. Sibiriche Brief, pp. iv + 104, Gottingen and Gotha. LAYNE, J. N. 1952. The os genitale of the red squirrel, _Tamiasciurus_. Jour. Mamm. 33:457-459, 1 fig., November 19. LINNAEUS, C. 1758. Systema Naturae. 1:1-824. MERRIAM, C. H. 1897. Notes on the chipmunks of the genus _Eutamias_ occurring west of the east base of the Cascade-Sierra system, with descriptions of new forms. Proc. Biol. Soc. Washington, 11:189-212, July 1. POCOCK, R. I. 1923. The classification of the Sciuridae. Proc. Zool. Soc. London, 1923:209-246, June. SAY, T. (_in_ Edwin James). 1823. Account of an expedition from Pittsburgh to the Rocky Mountains, performed in the years 1819 and 1820, under the command of Major Stephen H. Long. From the notes of Major Long, Mr. T. Say, and other gentlemen of the exploring party. Compiled by Edwin James. Vol. 1, pp. 1-503; Vol. 2, pp. 1-442 + appendix i-xcviii. SCHREBER, J. C. D. 1785. Saugthiere, 4:790-802. SIMPSON, G. G. 1945. The principles of classification and a classification of mammals. Bull. Amer. Mus. Nat. Hist., 85:xvi + 350, October 5. TROUESSART, E. L. 1880. Catalogue des mammiferes vivants et fossiles. Ordre des Rongeurs. Bull. Soc. d'Etudes Sci. d'Angers, 10:58-212. WHITE, J. A. 1951. A practical method for mounting the bacula of small mammals. Jour. Mamm. 32:125, February 15. _Transmitted June 26, 1953._ End of Project Gutenberg's Genera and Subgenera of Chipmunks, by John A. White