7. _Phenacomys intermedius celatus_, SA 2044, Quebec. 8. _Phenacomys intermedius intermedius_, WBQ 3-C-309, 5.4 mi. S Moran, Teton Co., Wyoming. 9. _Clethrionomys rufocanus_, 60438, 1 mi. NW Oho-ri, Korea, (_d_) ventral view. 10. _Clethrionomys gapperi_, 42108, 31 mi. N Pinedale, Wyoming. 11. _Clethrionomys rutilus_, 42865, 5 mi. NNE Gulkana, Alaska. 12. _Clethrionomys occidentalis_, FWS 30, Mary's Peak, Benton Co., Oregon. 13. _Clethrionomys glareolus_, 67100, Zermatt, Valais, Switzerland.] [Illustration: FIGURES 14-25. Bacula of _Microtus_. Unless indicated otherwise views are (_a_) of the dorsum, (_b_) the right side, and (_c_) the proximal end with dorsal surface upward. 14. _M. pennsylvanicus_, 42439, 1 mi. S, 2 mi. E Eagle Nest, Colfax Co., New Mexico; abnormality perhaps owing to injury; dorsal view. 15. _M. pennsylvanicus_, 42306, 5 mi. N, 26 mi. W Saguache, Colorado; dorsal view. 16. _M. pennsylvanicus_, 43043, 20 mi. NE Anchorage, Alaska, ventral view. 17. _M. pennsylvanicus_, 42430, 1 mi. S, 2 mi. E Eagle Nest, New Mexico. 18. _M. agrestis_, 67102, Gryon, Switzerland. 19. _M. montanus amosus_, 62241, 1/2 mi. E Soldier Summit, Wasatch Co., Utah. 20. _M. montanus nanus_, 57470, 2 mi. N, 2 mi. W Pocatello, Idaho. 21. _M. montanus fusus_, 42307, 5 mi. N, 26 mi. W Saguache, Colorado. 22. _M. arvalis_, 67101, Vidy, Switzerland, possibly not mature. 23. _M. guentheri_, 67104, Palestine. 24. _M. orcadensis_, 67106, Orkney Islands, orientation uncertain. 25. _M. fortis_, 63841, Chipo-ri, Korea, (_d_) ventral view.] [Illustration: FIGURES 26-39. Bacula of microtines. Unless indicated otherwise views are (_a_) of the dorsum, (_b_) the right side, and (_c_) the proximal end with the dorsal surface upward. 26. _M. (Pitymys) fatioi_, 67103, Zermatt, Switzerland, immature. 27. _M. (Pitymys) pinetorum_, 76834, 2 mi. N Baldwin, Douglas Co., Kansas. 28. _M. (Pitymys) pinetorum_, 68545, 1 mi. NE Pleasant Grove, Kansas. 29. _M. (Pitymys) quasiator_, 30709, Teocelo, Veracruz, (_d_) ventral view. 30. _M. (Pitymys) quasiator_, 19878, 5 km. N Jalapa, Veracruz. 31. _M. (Pedomys) ochrogaster_, 75036, 1 mi. N, 2 mi. E Oberlin, Kansas. 32. _M. (Stenocranius) miurus_, 51152, Lake Schrader, Brooks Range, Alaska. 33. _M. (Stenocranius) miurus_, 51169, Lake Schrader, Brooks Range, Alaska. 34. _M. (Stenocranius) gregalis_, 8059, "Eastern Europe." 35. _M. mexicanus mexicanus_, 63094, Valle de Bravo, Estado de México, México. 36. _M. mexicanus mogollonensis_, 63298, Mt. Taylor, Valencia Co., New Mexico. 37. _M. californicus_, 76828, 1 mi. NE Berkeley, California; (_d_) ventral view. 38. _M. (Arvicola) richardsoni_, 42454, 31 mi. N Pinedale, Sublette Co., Wyoming. 39. _M. richardsoni_, 37903, 23-1/2 mi. S, 5 mi. W Lander, Wyoming; distal end.] [Illustration: FIGURES 40-49. Bacula of microtines. Unless indicated otherwise views are (_a_) of the dorsum, (_b_) the right side, and (_c_) the proximal end with the dorsal surface upward.