1915.] 



THOMOMYS FUSCUS GROUP. 



131 



however, which shows great variation in that general region, and 

 probably mark only a local vaUey form partly cut off from the general 

 range of the species. 



Specimens examined. — Seven, from type locality. 



THOMOMYS HESPERUS Merriam. 

 West Coast Pocket Gopher. 

 (PI. vm, fig. 10.) 



Thomomys hesperus Merriam, Proc. Biol. Soc. Washington, XIV, 116, July 19, 1901. 



Type. — Collected at Tillamook, Tillamook County, Oregon, by J. 

 EUis McLellan, November 9, 1894. Type specimen in U. S. Nat. 

 Mus., Biological Survey collection. 



Distrihution. — Coast region of northwestern Oregon (fig. 5). 



Characters. — Size very small, with the small, pointed ears of the 

 fuscus group; color dark rich auburn; skull small, short, and rounded. 



Color. — Upperparts bright rich auburn, brighter than in helleri or 

 7nelanops, darker and richer than in mazama; nose and cheeks dusky; 

 large ear patch black; underparts lighter, more ochraceous; lining of 

 cheek pouches white; feet and tip of tail whitish. 



Slcull. — Short; braincase rather wide; rostrum short and wide; 

 posterior tip of nasals emarginate; bullae very small, short, and 

 rounded; basioccipital short and wide; pterygoids low and wide 

 apart; molars very smaU but apparently of about the same propor- 

 tions as those of fuscus. 



Measurements. — Type (9 ad.): Total length, 175; tail vertebrae, 

 54; hind foot, 24. Old male from Chintimini Mountains: 210, 60, 27. 

 Slcull (of type): Basal length, 27.3; nasals, 10.7; zygomatic breadth, 

 18; mastoid breadth, 15; interorbital breadth, 6; alveolar length 

 of upper molar series, 6. Skull of old male from Chintimini Moun- 

 tams: 30, 12.4, 20, 16.5, 6, 7. 



Rem/irJcs.— This is evidently a little, dark form of the fuscus group, 

 which seems to be isolated below the mouth of the Columbia River. 

 In color it strongly resembles melanops of the Olympic Mountains 

 and lielleri from farther south, but the tiny ears and general skuU char- 

 acters seem to place it in the fuscus group. Until a good series of 

 specimens of adult males is obtained its true position can not be fully 

 determined. An old male from the top of Chintimini Mountains 

 (near Corvalhs) seems to be the same, but may not be wholly typical. 



Specimens examined. — Total number, 6, as follows: 



Oregon: Chintimini Mountains (at 4,000 feet altitude), 1 old male; Tillamook, 5 

 (no adult males). 



