1915. ] 



THOMOMYS MONTICOLA GEOUP. 



123 



Shasta, 26; Mount Tallac, 36: Mount Unicorn, 3; Pacific Creek, 1: Pine City 

 (or Mammoth), 3; Pine Creek, 1; Pyramid Peak, 1; Robbins Creek (Lassen 

 County), 1; San Joaquin River (head), 1; Sierra Valley, 9; Silver Lake, 8; 

 Slippery Ford, 1; Sonora Pass, 4; Tallac, 1; Tenaya Lake, 2; Tuolumne 

 Meadows, 20; Warner Creek (Mount Lassen), 1; West Walker River, 2. 

 Nevada: Carson, 1; Glenbrook, 7; Sugar Loaf (Douglas County), 2. 



THOMOMYS MONTICOLA MAZAMA Merriam. 

 Mazama Pocket Gopher. 

 (PI. vm, fig. 2.) 



Thomomys mazama Merriam, Proc. Biol. Soc. Washington, XI, 214, July 15, 1897. 



Type. — Collected at Anna Creek (near Crater Lake), Mount 

 Mazama, Klamath County, Oregon, at 6,00G feet altitude, by 

 Edward A. Preble, September 3, 1896. Type specimen in U. S. Nat. 

 Mus., Biological Survey collection. 



Distribution. — Cascade and Siskiyou Mountains, Oreg., south in 

 California to the Trinity Mountams (fig. 5). 



CJiaracters. — ^About the size of monticola, but darker and richer 

 colored; ears nearly as large, and bullae larger and more rounded; 

 rostrum shorter, with less slender nasals; zygomatic arches more 

 abruptly spreadmg; mammse in 4 pairs, inguinal 2-2, pectoral 2-2. 



Color. — Summer pelage: Upperparts bright russet-brown; ear 

 patch blackish; nose plumbeous; underparts rich buff or ochraceous; 

 feet and tail whitish, tail usually gray above at base. Winter pelage 

 imknowm. Young slightly paler than adults. 



Slcull. — Not so long and slender as m monticola; nasals sharply 

 emarginate posteriorly and more spreading anteriorly; anterior base 

 of zygoma thin and prolonged against premaxilla. Dentition slightly 

 heavier than m monticola. 



Measurements. — Average of 4 topotypes (c?ad.): Total length, 

 209; tail vertebrae, 66; hind foot, 28. Average of 4 adult females: 

 202, 66, 28.7. Slull (of type, c?ad.): Basal length, 35; nasals, 13; 

 zygomatic breadth, 21; mastoid breadth, 17; mterorbital breadth, 

 6.5; alveolar length of upper molar series, 7.5. 



Remarks. — From monticola and pinetorum, mazama is readily dis- 

 tinguished by its shorter, wider, emarginate nasals and larger bullae; 

 from the douglasi group, by smaller size, slenderer skull, lighter den- 

 tition, V-shaped instead of U-shaped pterygoids, and deeper lateral 

 pits of palate; from quadratus, by larger ears, slenderer skull, and 

 emarginate nasals. It occupies the Canadian Zone and to some 

 extent the Transition also. 



Specimens examined. — Total number, 294, as follows: 

 California: Bear Creek (head of, Trinity County, at 6,400 feet altitude), 62; Bes- 

 wick (6 miles southwest, 6,000 feet), 1; Castle Lake (Siskiyou County, 

 5,400 feet), 8; Coffee Creek (north fork, Trinity County, 4,500 feet), 15; 

 Grizzly Creek (Trinity County, 6,000 feet), 2; Jackson Lake (Siskiyou 

 County), 13; Picard (Elgin Ranch), 1; Rush Creek (head of, Siskiyou County, 



