Dipodomys Kangaroo Rat 

 Maxilla without projecting wing before orbit; last upper cheek tooth 

 with a gap in the outer ring of enamel 



Microdipodops Dwarf Pocket Rat or Pocket Mouse 



98. Nasals extending well beyond incisors; skull about one inch long; cheek 



teeth with infoldings of enamel which may make teeth appear to have 

 several cusps 



Zapus Jumping Mouse 

 Nasals extending only slightly, if at all, beyond incisors; skull about two 

 inches long; no infoldings of enamel 99. 



99. Upper incisors smooth or with a shallow groove near inner edge 



Thomomys Western Pocket Gopher 

 Groove almost in center of incisor face, or with two grooves, the deeper 

 one toward the outer edge 100. 



100. With one groove almost in the middle of each upper incisor; two middle 

 upper cheek teeth with enamel plates on anterior side only 

 Cratogeomys Chestnut-faced Pocket Gopher 

 With two grooves in each upper incisor, the deeper one toward the outer 

 edge; upper cheek teeth with enamel on both anterior and posterior 

 sides 



Geomys Eastern Pocket Gopher 



GENERAL REFERENCES 



Anderson, R. M. 1946. Catalogue of Canadian Recent Mammals. National 

 Museum of Canada, Bull. No. 102, Biol. Series No. 31. Ottawa. 



Anderson, R. M. 1949. Methods of Collecting and Preserving Animals. Na- 

 tional Museum of Canada, Bull. No. 69, Biol. Series No. 18. 



Anthony, H. E. 1928. Field Book of North American Mammals. G. P. Put- 

 nam's Sons. New York. 



Audubon, J. J. and Bachman, J. 1845'1852. The Viviparous Quadrupeds of 

 North America. 



Bailey, J. W. 1946. Mammals of Virginia. Williams Printing Co. Rich' 

 mond. Privately Published. 



Bailey, V. 1931. Mammals of New Mexico. No. Amer. Fauna, No. 53. 



Barnes, C. T. 1927. Utah Mammals. Bull. Univ. Utah. Vol. 17, No. 12. 



Burt, W. H. 1946. The Mammals of Michigan. The Univ. of Michigan 

 Press. Ann Arbor, Mich. 



Calahane, V. H. 1948. Mammals of North America. Macmillan Co. New 

 York. 



Cory, C. B. 1912. The Mammals of IlHnois and Wisconsin. Field Museum 

 Nat. Hist., Zool. Series, Vol. 11. 



Dalquest, W. W. 1948. Mammals of Washington. Univ. of Kansas Pub., 

 Museum of Nat. Hist., Vol. 2. Lawrence, Kansas. 



Dice, L. R. 1927. A Manual of the Recent Wild Mammals of Michigan. 

 Michigan Handbook Series, No. 2. Univ. of Michigan. Ann Arbor. 



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