Goldman — Five New Mammals from Mexico and Arizona. 135 

 Neotoma albigula mearnsi subsp. nov. 



MEARNS WOOD RAT. 



Type from Tinajas Altas, near international boundary, southwestern 

 Arizona. No. 202,981, male adult, U. 8. National Museum (Biological 

 Survey Collection), collected by E. A. Goldman, November 21, 1913. 

 Original number 22, .300. 



General characters. — Closely allied to N. a. albigula but paler, the 

 ground color of upperparts light buff instead of warm buff or light 

 ochraceous-buff of Ridgway, 1912, as in that form; underparts purer 

 ■white, the areas of basally plumbeous fur more restricted ; tail less sharply 

 bicolor, grayer above. 



Color. — Type (fresh pelage): Upperparts light buff, nearly pure on 

 cheeks, flanks and outer sides of limbs, the top of head and back rather 

 thinly lined or overlaid with an admixture of black-tipped hairs ; under- 

 parts, including lips, sides of muzzle, and inner sides of limbs white, the 

 fur pure white to roots except along flanks and sides of abdomen where 

 it is pale plumbeous basally; ears grayish, edged with white; feet white; 

 tail grayish above (light and dark hairs intermixed), white below. 



Skull. — Like that of N. a. albigula; palate concave posteriorly and 

 first upper molar with antero-internal reentrant angle shallow, as in the 

 typical form. 



Measurements. — Type: Total length, 337; tail vertebr?e, 165; hind 

 foot, 35. Average of two adult topotypes: 332 (329-335); 158 (157-159) ; 

 32 (31.5-32.5). Skull (type): Greatest length, 43.2; zygomatic breadth, 

 21.5; interorbital breadth, 5.9; length of nasals, 16; length of anterior 

 palatine foramina, 8.6; length of palatal bridge, 7.7; length of upper 

 molar series, 8.5. 



Remarks. — The pallid coloration of this form readily distinguishes it 

 from N. a. albigula whose range includes most of Arizona, New Mexico, 

 eastern Texas and much of northern Mexico. N. a. mearnsi is probably 

 restricted to the extremely arid desert area extending from near the type 

 locality southward along the eastern side of the Gulf of California — a 

 region largely covered with shifting, whitish sand. Close comparison 

 with N. a. melanura and N. a. seri of southern Sonora is unnecessary, 

 both being darker forms with differing cranial details. The skull of 

 N. a. seri is somewhat smaller and less massive, with narrower frontal 

 region, smaller interparietal and slightly smaller audital bullae. Some of 

 the specimens of N. a. albigula from Sonoyta, Sonora, are pale and 

 apparently show gradation toward the present form. The pallid colora- 

 tion of three or four examples of N. albigula from Tinajas Altas and 

 vicinity was pointed out by Mearns* who contrasted them with the 

 darker animals inhabiting the Gila River bottom. It was not until the 

 accession of new material that the necessity of recognizing a new form 

 became apparent. It is named for Dr. E. A. Mearns who collected spec- 

 imens at the type locality more than 20 years ago. 



Specimens examined. — Ten, all from southwestern Arizona as follows : 



* Mammals of the Mexican Boundary, Bui. 56, part I, U. S. Nat. Mus., p. 480, 1907. 



