306 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



also observed at Laboree's ranch and the Tucson Mountains, on the 

 road to Tucson, Arizona. In December, 1893, and January following, 

 while camped at Pozo de Luis, Sonora, it appeared to be uncommon. 

 It was said to abound at Sonoyta, Sonora, but not many were seen 

 owing to the cold weather. One was noted at Santo Domingo, on the 

 Sonoyta, and sonic species of ground-squirrel was said to occur numer- 

 ously on Nariz Mountain. At Quitobaquita, Pima County, Arizona, 

 we found it common from January 25 to February 8, 1894. Sonic 

 were seen on rough granite hills, others on the Hat river bottom over- 

 grown with the creosote bush, sagebrush, and greasewood. Those 

 taken in traps had mesquite beans in their cheek-pouches. 



AMMOSPERMOPHILUS HARRISII SAXICOLA (Mearns). 

 ROCK-SGXTIRREL. 



Sperrnophilus harrisii saxicolus Mearns, Proc. U. S. Nat. Mus., XVIII, No. 1075, 



May 23, 1896, p. 414 (advance sheet published Mar. 25, L896). 

 [Sperrnophilus harrisii] saxicolus, Elliot, Field Col. Mus., Zoiil. Ser., II, 1901, 



p. 86 (Synop. Mam. X. Am.). 

 Sperrnophilus h<in-ixii saxicola, Miller and Rehn, Proc. Boat. Soc. Nat. Hist., 



No. 1, XXX, Dec 27, 1901, p. 51 (Syst. Results Study N. Am. Mam. to close 



of 1900). 

 [(Melius harrisi] saxicola, Elliot, Field Col. Mus., Zool. Ser., IV, 1904, p. 142 



i Mam. Mid. Am.). 

 Citellus {Ammospermophitus) harrisi saxicolus, Trouessart, fatal. Mam., Suppl., 



1904, p. 335. 



Type-locality. — Tinajas Altas, Gila Mountains, Yuma County, Ari- 

 zona. (Type, skin and skull. No. 59869, U. S. National Museum.) 



Geographical range. — Mountain ranges of the Western Desert, in 

 the Lower Sonoran Zone of Arizona and Sonora. 



Description. — Similar to Atnmospermophilits harrisii, but much 

 paler, with the light markings every where increased in extent and 

 with a much longer tail. Length, 245 mm.; tail vertebra?, 95; ear 

 from crown, 5; hind foot, 40. Skull (tig. 48), 40 by 23. Mamma, 5 

 pairs. 



Remarks. — This is a loug-tailed. pallid, desert race, inhabiting bare 

 granite ranges of mountains, extending in a .southeasterly direction 

 from the Gila River, in southwestern Arizona (Yuma County), into 

 western Sonora. 



Ammospermophilus harrisii was described by Audubon and Bach- 

 man from a specimen from an unknown locality. In naming the present 

 subspecies it became expedient to restrict the name harrisii to the 

 darker form, which was found in the Elevated Central Tract, along 

 the Mexican Boundary Line, from the Santa Cruz Valley westward as 

 far as the Sonoyta, where intergrades were taken at Quitobaquita. 



Habits and /<><■></ distribution. — 1 heard the twitter of one of these 

 rock-squirrels in the mountains five miles east of Tule Wells, February 



