XII CONTENTS. 



Order Rodentia — Continued. 



Superfamily Sciuroidse — Continued. 

 Family Geomyidoe — Continued. 



Subfamily Geomyidae — Continued. Page. 



Genus Orthogeomys Merriam 261 



Genus Heterogeomys Merriam 261 



Genus Macrogeomys Merriam 262 



Genus Zygogeomys Merriam 263 



Family Heteromyidte 263 



Genus Jleteromys Desmarest 263 



Subgenus Heteromys Desmarest 264 



Subgenus Xylomys Merriam 266 



Genus Liomys Merriam 266 



Genus Perognathus Wied 272 



Subgenus Perognathus Wied 272 



Subgenus Chtetodipus Merriam 280 



Genus Dipodomys Gray 287 



Genus Microdipodops Merriam 297 



Family Castoridae , 298 



Genus Castor Linnseus 298 



Superfamily Muroida? 300 



Family Cricetidse 300 



Subfamily Cricetinae 300 



Genus Onychomys Baird 300 



Genus Reithrodontomys Giglioli 306 



Subgenus Reithrodontomys Giglioli 306 



Subgenus Aporodon Howell 314 



Genus Baiomys True 317 



Genus Peromyscus Gloger 318 



Subgenus Haplomylomys Osgood 318 



Subgenus Peromyscus Gloger 323 



Subgenus Megadontomys Merriam 350 



Subgenus Ochrotomys Osgood 351 



Subgenus Podomys Osgood 352 



Genus Oryzomys Baird 352 



Subgenus Oryzomys Baird 352 



Subgenus Oligoryzomys Bangs 362 



Subgenus Melanomys Thomas 363 



Genus Neacomys Thomas 364 



Genus Zygodontomys Allen 364 



Genus Megalomys Trouessart 365 



Genus Tylomys Peters 365 



Genus Ototylomys Merriam 366 



Genus Nectomys Peters 367 



Genus Rheomys Thomas 367 



Genus Nyctomys Saussure 367 



Genus Rhipidomys Tschudi 368 



Genus CEcomys Thomas 369^ 



Genus Sigmodon Say and Ord 369 



Genus Scotinomys Thomas 374 



Genus Neotomodon Merriam 375 



Genus Nelsonia Merriam 376 



Genus Teanopus Merriam 376 



