1911] Taijlor: Mammals of the 1909 Nevada Expedition. 285 



Nevada differ to a comparable degree even from specimens of the 

 same species from the Bkie INIountains of Oregon. These facts 

 tend to show that these ratios are of no great significance in the 

 diagnosis of species of Zapus. 



Ratios of Tail Vertebrae and Hind Foot to Total Length in Various 

 Western Species op Zapus* 



Zapus princeps oregonus 



(typical) 

 Zapus princeps oregonus 



from Pine Forest Mts. 

 Zapus major 

 Zapus nevadensis 

 Zapus trinotatus alleni 

 Zapus montanus 

 Zapus paci-ficus 

 Zapus orarius 



* Based on nieasnrements given in Preble's (1899) revision of the gronp. 



I have accepted C. H. ]\Ierriam's and Preble's identification 

 in view of the material at their disposal. From a study of the 

 characters of the Pine Forest Mountain animal and a careful 

 checking up of the descriptions of other species, I have, however, 

 reached the conclusion that while perhaps referable to oregonus, 

 it is nevertheless not typical of that form, at least as character- 

 ized in the original description (Preble, 1899, p. 24), but repre- 

 sents an incipient species, not sufficiently differentiated to war- 

 rant designation by name. The following species of Zapus are 

 among those described from western North America: (1) Zapus 

 princeps oregonus Preble, tj'pe locality Elgin, Blue ^Mountains, 

 Union County, Oregon; (2) Zapus major Preble, Warner Moun- 

 tains, Lake County, Oregon; (3) Zapus nevadensis Preble, Ruby 

 ^Mountains, Elko County, Nevada; (4) Zapus nwnfanus C. H. 

 ]\Ierriam, Crater Lake, Mount Mazama, Klamath County, Oregon ; 

 (5) Zapus pacific us C. H. Merriam, Prospect, Rogue River Val- 

 ley, Jackson County, Oregon; (6) Zapus orarius Preble, Point 

 Reyes, Marin County, California; (7) Zapus trinotatus Rhoads, 

 Lulu Island, mouth of Fraser River, British Columbia; and (8) 

 Zapus trinotatus alleni Elliot, Pyramid Peak, Lake Tahoe, Call- 



