1914] Grinnell: Mammals and Birds of the Colorado Valley 217 



because of much seasonal variation in tone of browns and blues through 

 fading and abrasion, and because of wide individual variation in extent 

 of chestnut areas. General size, too, is an inconstant feature (see Grin- 

 nell and Swarth, 1913, p. 318). 



CHECK-LIST OF MAMMALS 



1. Ovis canadensis nelsoni Merriam 



2. Odocoileus hemionus eremicus (Mearns) 



3. Ammospermophilus harrisi harrisi (Audubon and Bachman) 



4. Ammospermophilus leucurus leucurus (Merriam) 



5. Citellus tereticaudus tereticaudus (Baird) 



6. Castor canadensis frondator Mearns 



7. Peromyscus maniculatus sonoriensis (Le Conte) 



8. Peromyscus crinitus stephensi Mearns 



9. Peromyscus eremicus eremicus (Baird) 



10. Sigmodon hispidus eremicus Mearns 



11. Beithrodontomys megalotis deserti J. A. Allen 



12. Neotoma albigula venusta True 



13. Neotoma intermedia desertorum Merriam 



14. Ondatra zibethica pallida (Mearns) 



15. Thomomys chrysonotus Grinnell 



16. Thomomys albatus Grinnell 



17. Dipodomys deserti deserti Stephens 



18. Dipodomys merriami merriami Mearns 



19. Perognathus bombycinus Osgood 



20. Perognathus formosus Merriam 



21. Perognathus penicillatus penicillatus Woodhouse 



22. Perognathus intermedins Merriam 



23. Perognathus spinatus spinatus Merriam 



24. Lepus californicus deserticola Mearns 



25. Sylvilagus auduboni arizonae (J. A. Allen) 



26. Felis oregonensis browni Merriam 



27. Lynx eremicus eremicus Mearns 



28. Canis ochropus estor Merriam 



29. Vulpes maerotis arsipus Elliot 



30. Urocyon cinereoargenteus scotti Mearns 



31. Mephitis estor Merriam 



32. Spilogale arizonae arizonae Mearns 



33. Taxidea taxus berlandieri Baird 



34. Procyon pallidus Merriam 



35. Corynorhinus maerotis palleseens Miller 



36. Antrozous pallidus pallidus (Le Conte) 



37. Myotis occultus Hollister 



38. Myotis californicus pallidus Stephens 



39. Myotis velifer (J. A. Allen) 



40. Pipistrellus hesperus hesperus (II. Allen) 



41. Eptesicus fuscus (Beauvois) 



42. Nyctinomus mexicanus Saussure 



43. Macrotus californicus Baird 



