450 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Description. — This race is much, smaller, paler, and grayer than 

 Sigmodon hispidus texianus or S. h. arizonse, and lacks their brown 

 color, which is replaced by gray. Above soiled grayish, finely mixed 

 with black. Below pure white. Tail quite hairy, with the median 

 upper surface dusky. Ear much larger, actually as well as relatively, 

 than that of S. Ji. texianus. Length, 242 mm.; tail vertebrse, 103; 

 ear from crown, 14; hind foot, 30. Skull 

 (about) 30 by 18 mm. (See also p. 453). The 

 teeth are shown in fig. 111. 



Comparisons. — This, the smallest of the four 

 geographical races of Sigmodon hispidus found on 

 the Mexican line, differs from the almost equally 

 pallid form of the Western Desert (Sigmodon hispi- 

 " '' dus eremicus) in being of a grayish instead of a 



Fig. 111.— Sigmodon his- ,, . , , , . i i . ■- , i , ■ i 



PIDU3 BERLANDiEKi. ycllowish color, and m lackmg the termmal 

 ckown OF MOLAE TEETH, expauslou of thc uasals. The cottoii-rat of the 



a, UPPER series; b, ^.'^ ,n/-i,im j/r>7 • s- 1 



LOWER SERIES. ' liilcvated (Jeutral iTact (iS. A. ansonas) IS SO much 



larger and darker than either of the desert forms 



(berlandieri and eremicus) that further comparison is unnecessary. 



SIGMODON HISPIDUS ARIZON.^; Mearns. 

 ARIZONA COTTON-RAT. 



Sigmodon hispidus arizonse Meaens, Bull. Am. Mus. Nat. Hist., II, p. 287, Feb. 21, 1890 

 (original description). — ^Allen, Bull. Am. Mus. Nat. Hist., Ill, 1891, p. 208 (in 

 text); V, 1893, p. 28 (" One specimen from Granados [on the Yaqui River], Nov. 

 16"); VII, 1895, p. 220 (critical remarks on a dozen specimens taken at Fairbank, 

 on the San Pedro River, Arizona). — Milleb and Rehn, Proc. Bost. Soc. Nat. Hist., 

 XXX, No. 1, Dec. 27, 1901, p. 90 (Syst. Results Study N. Am. Mam. to close of 

 1900); XXXI, Aug. 27, 1903, p. 80 (Syst. Results Study N. Am. Mam. during the 

 years 1901 and 1902) .—Bailey, Proc. Biol. Soc. Washington, XV, p. 108, June 2, 

 1902 (Synopsis of the North American Species of Sigmodon) . 

 [Sigmodon hispidus] arizonse, Elliot, Field Col. Mus., Zool. Ser., II, 1901, p. 144 



(Synop. Mam. N. Am.). 

 [Sigmodon] hispidus arizonx, Elliot, Field Col. Mus., Zool. Ser., IV, 1904, p. 228 (Mam. 

 Mid. Am.). 



KSM'4a of the Hopi Indians. 



Tu'-sa or Ahr^me-ld of the Hualapai Indians. 



Type-locality. — Alfalfa fields on the Verde River at Fort Verde, 

 Yavapai County, Arizona. (Type, skin and skull. Cat. No. iff^, 

 American Museum of Natural History.) 



GeograpJiical range. — Inhabits the Elevated Central Tract from Fort 

 Verde, Arizona, tt) Granados, in Sonora, Mexico. 



Description. — Size large. Coloration darker than that of the desert 

 forms ipallidus and eremicus) on either side of its range, but paler 

 than in the coast forms (hispidus, littoralis, texianus, etc.). Above 

 light yellowish brown, mixed with ashy, lined rather sparingly with 

 black; below white; pelage everywhere plumbeous at base; tail 

 dusky above, whitish below. Ears large, orbicular, clothed with 



