5. Comments on the taxonomy and geographic distribution of some North American rabbits. By E. Raymond Hall and Keith R. Kelson. Pp. 49-58. October 1, 1951. 6. Two new subspecies of Thomomys bottae from New Mexico and Colorado. By Keith R. Kelson. Pp. 59-71, 1 figure in text. October 1, 1951. 7. A new subspecies of Microtus montanus from Montana and comments on Microtus canicaudus Miller. By E. Raymond Hall and Keith R. Kelson. Pp. 73-79. October 1, 1951. 8. A new pocket gopher (Genus Thomomys) from eastern Colorado. By E. Raymond Hall. Pp. 81-85. October 1, 1951. 9. Mammals taken along the Alaskan Highway. By Rollin H. Baker. Pp. 87-117, 1 figure in text. November 28, 1951. *10. A synopsis of the North American Lagomorpha. By E. Raymond Hall. Pp. 119-202, 68 figures in text. December 15, 1951. 11. A new pocket mouse (Genus Perognathus) from Kansas. By E. Lendell Cockrum. Pp. 203-206. December 15, 1951. 12. Mammals from Tamaulipas, Mexico. By Rollin H. Baker. Pp. 207-218. December 15, 1951. 13. A new pocket gopher (Genus Thomomys) from Wyoming and Colorado. By E. Raymond Hall. Pp. 219-222. December 15, 1951. 14. A new name for the Mexican red bat. By E. Raymond Hall. Pp. 223-226. December 15, 1951. 15. Taxonomic notes on Mexican bats of the Genus Rhogeëssa. By E. Raymond Hall. Pp. 227-232. April 10, 1952. 16. Comments on the taxonomy and geographic distribution of some North American woodrats (Genus Neotoma). By Keith R. Kelson. Pp. 233-242. April 10, 1952. 17. The subspecies of the Mexican red-bellied squirrel, Sciurus aureogaster. By Keith R. Kelson. Pp. 243-250, 1 figure in text. April 10, 1952. 18. Geographic range of Peromyscus melanophrys, with description of new subspecies. By Rollin H. Baker. Pp. 251-258, 1 figure in text. May 10, 1952. 19. A new chipmunk (Genus Eutamias) from the Black Hills. By John A. White. Pp. 259-262. April 10, 1952. 20. A new piñon mouse (Peromyscus truei) from Durango, Mexico. By Robert B. Finley, Jr. Pp. 263-267. May 23, 1952. 21. An annotated check-list of Nebraskan bats. By Olin L. Webb and J. Knox Jones, Jr. Pp. 269-279. May 31, 1952. 22. Geographic variation in red-backed mice (Genus Clethrionomys) of the southern Rocky Mountain region. By E. Lendell Cockrum and Kenneth L. Fitch. Pp. 281-292, 1 figure in text. November 15, 1952.