120 Bailey — New Mammals from Western Texas. 



age of 10 adults: 193; 60; 26. Sk^ill of type: basal length 34.5; nasals 

 13; zygomatic breadth 22; mastoid breadth 18; alveolar length of upper 

 molar series 7. 



Remarks. — The affinity of the present form with the fulvus group is 

 shown by the general form of skull and by the wide, flat basioccipital 

 with sharp instead of rounded lateral edges as well as by the similarity 

 of color. 



Thomomys aureus lachuguilla subsp. nov. 



Type from arid foothills near El Paso, Texas, No. 110,336, U. S. 

 National Museum, Biological Survey Collection, $ ad. Collected 

 September 24, 1901, by Vernon Bailey. Original No. 7858. 



General characters. — A small, light yellowish form of the aureus group 

 with big bullae and narrow basioccipital. 



Color. — Summer pelage: Upperparts dull ochraceous; belly buffy or 

 pale cinnamon. Winter pelage: Brighter ochraceous above and light 

 buft'y below. 



Skull. — Slender, with conspicuously slender rostrum; bullae full and 

 rounded with basioccipital narrowly constricted between; interparietal 

 small and rounded or quadrate; premaxillae slender and projecting well 

 back of nasals; upper incisors bent down at right angles to axis of skull. 



Measurements. — Type: total length 215; tail 65; hind foot 29. Aver- 

 age of 4 adults: 201; 61; 27.4. 



Remarks. — Named for the Agave laclmguilla which furnishes its 

 favorite food. 



