4 Contents 



Order Ungulata. Hoofed Mammals 57 



Family Cervidae. Deer, Moose, Elk, Caribou 58 



Key to the Genera 59 



Key to the Species 59 



Family Bovidae. Bison, Oxen, Sheep, etc. 86 



Order Glires. Gnawing Mammals 97 



Key to the Suborders and Families 98 



Family Sciuridae. Squirrels, Woodchucks, etc 98 



Key to the Genera 99 



Key to the Species 99 



Subfamily Pteromyinas. Flying Squirrels 102 



Subfamily Sciurinas. Squirrels, Chipmunks, etc 108 



Subfamily Mannotinae. Prairie Squirrels, Woodchucks, etc. . 137 



Family Castoridae. Beavers 15S 



Family Muridae. Rats and Mice 171 



Key to the Genera 171 



Key to the Species 173 



Subfamily Murinae. Old World Rats and Mice . . . .176 



Subfamily Cricetinae. White-footed Mice, Cotton Mice, etc. . 183 



Key to the Species . 183 



Subfamily Neotominas. Wood Rats 204 



Subfamily Microtinae. Meadow Mice or Voles, Lemming 



Mice, and Muskrats 208. 



Key to the Subgenera and Species of Mlcrotus . . . . .213 



Family Geomyidae. Pocket Gophers 239 



Family Zapodidae. Jumping Mice 246 



Subfamily Zapodinae. American Jumping Mice .... 246 



Family Erethizontidag. American Porcupines 253 



Subfamily Erethizontinae. American Porcupines . . . 254 



Family Leporidas. Hares and Rabbits 259 



Key to the Genera 261 



Key to the Species -. 261 



Order Fer^. Flesh Eaters 275 



Key to the Families 277 



Family Felidae. The Cats 277 



Subfamily Felinae. Panthers, Lynx, Wild Cat, etc. . . . 279 



Key to the Genera 279 



Key to the Species 279 



Family Canidas. Wolves and Foxes 296 



Key to the Genera 298 



Key to the Species 299 



Family Mustehdas. Otters, Minks, Weasels, Skunks, Badgers, etc. 327 



