110 Hferriftm JVe*r /Species of Thomomys. 



Cranial character*. Zygomata strongly spreading, broader behind than 

 in front, with well developed anterior angle; temporal impressions 

 marked; interparietal subquadrate becoming subtriangular in old age: 

 nasals narrowly cuneate, notched behind, and falling well short of pre- 

 maxillae; bull* medium;- under jaw very long, the postcoronoid notch 

 narrow and completely covered by coronoid process. From baileyi, its 

 nearest known relative, it may be distinguished by narrower nasals, nar 

 rower interorbital region, strikingly narrower and differently shaped 

 postcoronoid notch, and less protruding upper incisors. 



Measurement ft. Type specimen ( 9 ad.): total length 196; tail verte- 

 braR 60; hind foot 28. An adult male from type locality: total length 

 207; tail vertebrae 59; hind foot 28.5. 



Thomomys cabezonae sp. nov. 



Type from Cabe/on, San Gorgon io Pass, California. No. 58,987, $ 

 ad., U. S. National Museum, Biological Survey Collection. June 8, 

 1898. C. P. Streator. Original No. 2906. 



Character*. Size medium, but smaller than perpallidus or ai<rfns; 

 ears rather large; tail long: color varying from butfy ochraceous (as in 

 aureus) to dull salmon brown. 



Color, Upperparts buffy ochraceous, buffy gray, or even (in the type 

 and darkest specimen of 7 from type locality) dull drab-brown on back, 

 becoming buffy ochraceous on sides: nose, lips, chin and opening of 

 cheek pouches dusky; underparts varying from whitish to pale salmon. 



Cranial character*. Skull small, angular: zygomata moderately 

 spreading, broadest anteriorly and sharply angular in adults; temporal 

 ridges marked; interparietal rectangular, broader than long in immature 

 skulls; nasals long, with straight sides (not constricted), notched behind, 

 and not reaching near tips of premaxillte; bull a 1 medium. Compared 

 with aureus and perpallidus the skull and jaw are strikingly smaller and 

 lighter, the interparietal quadrangular instead of sub-triangular, the 

 bullae very much smaller, Compared with perpallidus the zygomata are 

 much less spreading. 



Measurements. Type specimen ( $ ad.): total length 235; tail verte 

 brae 79; hind foot 30. Average of 7 adults from type locality: total 

 length 222; tail vertebrae 78; hind foot 30. 



Thomomys aureus pervagus subsp. nov. 



Type from Espanola, New Mexico. No. 58,293, $ ad., U. S. National 

 Museum, Biological Survey Collection. January 4, 1894. J. Alden Lor- 

 ing. Original No. 1548. 



Characters. Similar to aureus but much darker, color chestnut ful 

 vous instead of golden fulvous; upperparts dull chestnut fulvous, the 

 middle part of back broadly mixed with black-tipped hairs; nose and 



