1915.] 



THOMOMYS TALPOIDES GEOUP. 



101 



and more rounded than in talj)oides; anterior arm of basioccipital 

 very narrow: nasals slenderer, especially at posterior tips, which are 

 variously rounded, truncate, or slightly emarginate in the topotype 

 series; interparietal small and triangular. Dentition conspicuously 

 hghter than in talpoides. 



Measurements. — Topotype (c?ad.): Total length, 205; tail verte- 

 brae, 66; hind foot, 28.5. Average of 7 female topotypes: 204, 60, 27. 

 STcuU (topotype, c?ad.):^ Basal length, 33.4; nasals, 13; zygomatic 

 breadth, 22; mastoid breadth, 19.5; interorbital breadth, 11.5: 

 alveolar length of upper molar series, 7. 



Remarks. — In general appearance clusius is nearer talpoides than 

 is the larger and paler huUatus, which separates their ranges and evi- 

 dently grades into one on the north and the other on the south. It 

 is not improbable, however, that clusius and talpoides meet in a 

 narrow Transition Zone strip along the eastern base of the Rocky 

 Mountains above the Upper Sonoran limits of huUatus. At the type 

 locahty and over most of its range clusius is found in Transition 

 Zone sage-brush country. 



Specimens examined. — Total number, 106, as follows: 

 Colorado: Avalo, 5; Boulder, 1; Canadian Creek (North Park), 6; Colorado 

 Springs, 7; Estes Park, 1; Flagler, 7; Gold Hill, 1; Limon, 1; Pawnee Buttes, 

 1; Siebert (8 miles south), 1. 

 Wyoming': Bear Creek (3 miles southwest of Laramie Peak, at 7,500 feet alti- 

 tude), 1; Beaver, 1; Bridgers Pass, 14; Casper (40 miles southwest), 4; Chey- 

 enne, 7; Dayton, 1; Douglas, 2; Ferris Mountains (7,800 to 9,400 feet), 4; 

 Fetterman, 1; Fort Russell, 1; Fort Steele, 3; Green Mountains (8,000 feet), 

 2; Islay, 2; Laramie Mountains (east of Laramie, at 8,500 and 9,000 feet), 3; 

 Little Bear Creek (20 miles southeast of Chugwater), 1; Miners Delight, 1; 

 Myers\dlle, 2; Myersville (22 miles southeast), 1; Pass (now Parkman), 2; 

 Pine Bluffs, 2; Rattlesnake Mountains (north base), 3; Rawhide Butte 

 (5,400 feet), 1; Red Bank, 1; Rock Creek, 1; Sherman, 2; Sliirley Mountains 

 (7,600 to 8,800 feet), 4; Springliill (12 miles north of Laramie Peak), 2; Sun, 

 3; Wheatland (15 miles southwest, at 5,200 feet), 1; Woods, 2. 



THOMOMYS TALPOIDES BULLATUS Bailey. 

 Sage Pocket Gopher. 



(PL YIl, fig. 2.) 



Thomomys talpoides hullatus Bailey, Proc. Biol. Soc. Washington, XXVII, 115, July 

 10, 1914. 



Type. — Collected at Powderville, Custer County, Montana, by Dr. 

 A. K. Fisher, July 21, 1893. Type specimen in U. S. A"at. Mus., 

 Biological Survey collection. 



Distribution. — Plains of eastern Montana, northeastern Wyoming, 

 and western South Dakota; north to Mediciue Hat, Alberta (fig. 10). 



Characters. — Size of talpoides, but with larger audital bullge, lighter 

 dentition, and brighter colors; mamm^ usually in 6 pairs; young, 5 to 7. 



1 No. 25534, U. S. Nat. Mus. 



