1927. A biological survey of North Dakota. N. Amer. Fauna, 49:vi+ 226, 21 pls., 8 figs. in text, January 8. 1932. Mammals of New Mexico. N. Amer. Fauna, 53:1-412, 22 pls., 57 figs. in text, March 1. BAIRD, S. F. 1858. Explorations and surveys for a railroad route from the Mississippi River to the Pacific Ocean. War Department. Mammals, Part I, xxxii + 757, pls. 17-60, 35 figs. in text, July 14. DALQUEST, W. W. 1948. Mammals of Washington. Univ. Kansas Publ., Mus. Nat. Hist., 2:1-444, 140 figs. in text, April 9. DAVIS, W. B. 1939. The Recent mammals of Idaho. The Caxton Printers, Caldwell, Idaho, 400 pp., 2 full page half tones, 33 figs. in text, April 5. DURRANT, S. D. 1952. Mammals of Utah, taxonomy and distribution. Univ. Kansas Publ., Mus. Nat. Hist., 6:1-549, 91 figs. in text, 30 tables, August 10. ELLERMAN, J. R. 1941. The families and genera of living rodents. Volume II. Family Muridae. The British Museum. xii + 690 pp., 50 figs. in text, March 21. FINDLEY, J. S. 1954. Competition as a possible limiting factor in the distribution of _Microtus_. Ecology, 35:418-420, July. HALL, E. R., and E. L. COCKRUM 1952. Comments on the taxonomy and geographic distribution of North American microtines. Univ. Kansas Publ., Mus. Nat. Hist., 5:293-312, November 17. 1953. A synopsis of the North American microtine rodents. Univ. Kansas Publ., Mus. Nat. Hist., 5:373-498, 149 figs. in text, January 15. HIBBARD, C. W. 1940. A new Pleistocene fauna from Meade County, Kansas. Trans. Kansas Acad. Sci., 43:417-425, December 23. HOWELL, A. B. 1926. Anatomy of the wood rat. Monogr. Amer. Soc. Mamm. No. 1, x + 225 pp., 35 figs., Williams and Wilkins Co., Baltimore. SNYDER, D. P. 1954. Skull variation in the meadow vole (_Microtus p. pennsylvanicus_) in Pennsylvania. Annals of the Carnegie Museum, 33:201-234, September 21. WARREN, E. R. 1942. The mammals of Colorado. Univ. Oklahoma Press, xviii + 330 pp., 50 pls. _Transmitted June 30, 1955._