| Neotropical | | 39° N. | 51. Hesperomys | 16 | Temperate N. America | Neotropical 52. _Neotoma_ | 7 | Temperate N. America | 53. _Sigmodon_ | 2 | S. and S. E. States | 54. Arvicola | 27 | Texas and California | Palæarctic | | to Hudson's Bay | 55. Myodes | 3 | N. United States to | N. Palæarctic | | Arctic Reg. and | | | Greenland | 56. _Fiber_ | 1 | All N. America | Mexico | | | DIPODIDÆ. | | | 57. _Jaculus_ | 1 | Pennsylvania to Canada| | | and California | | | | SACCOMYIDÆ. | | | 58. _Dipodomys_ | 5 | New Mexico to Columbia| | | River and Carolina | 59. _Perognathus_ | 6 | New Mexico to British | | | Columbia | 60. _Thomomys_ | 2 | Upper Missouri to | | | Hudson's Bay | 61. _Geomys_ | 5 | New Mexico to Alabama | | | and Nebraska | 62. _Saccomys_ | 1 | N. America | | | | CASTORIDÆ. | | | 63. Castor | 1 | N. Mexico to Labrador | Palæarctic | | | SCIURIDÆ | | | 64. Sciurus | 18 | N. America to Labrador| All regs. but | | | Australian 65. Sciuropterus | 4 | California & E. States| Palæarctic, Oriental | | northwds. | 66. Tamias | 4 | Mexico and Virginia | Mexico, N. Asia | | to Canada | 67. Spermophilus | 15 | N., W., & Central | Palæarctic | | N. America | 68. _Cynomys_ | 2 | Rio Grande to Missouri| | | (Central) | 69. Arctomys | 4 | Virginia and Nebraska,| N. Palæarctic | | northws. | | | | HAPLOODONTIDÆ. | | | 70. _Haploodon_ | 2 | California and British| | | Columbia | | | | CERCOLABIDÆ | | | 71. _Erethizon_ | 2 |Pennsylvania to Canada,| | | & Pacific coast | LAGOMYIDÆ. | | | 72. Lagomys | 1 | Rocky Mountains, 42° | Palæarctic