Robert B. Finley

“ Four adults and one subadult from Trinidad are intergrades between N. m. scopulorum and N. m. fallax, perhaps more nearly resembling the former. In pelage they are indistinguishable from specimens of fallax from Gold Hill (the type locality) , less buff than most individuals of scopulorum from Otero, Prowers, and Baca counties. The skulls of the three fully mature adults are large with a wide zygomatic breadth, large rostrum, and large upper incisors [Pg 533] as in scopulorum; but the upper molars are small and the bullae are rather small and narrow as in fallax. ”

“ Some cottonwoods grow along the river, which is almost dry most of the time. East of the river is a flat plain or valley of adobelike soil a few miles wide beyond which extends a rough area of dark lavas. ”

“ The skull of this rat has narrower nasals than other adults from Two Buttes and a longer interparietal with a posterior median angle.
Subadult taken in April at Regnier: completing postjuvenal (first) molt; new pelage fairly long and thick everywhere except on neck and upper back, where covered by remaining juvenal pelage; upper parts of new pelage duller than in adults, sides less buffy, more grayish; juvenal pelage grayer than new pelage; new pelage indistinguishable from same pelage (second pelage of first year) of N. m. fallax. ”

“ The basal gray coloration, where it is present along the sides of the venter, forms only a narrow intermediate color band extending not more than one third the length of the hairs. An extensive area of the throat, breast, axillae, median belly, and inguinal region is covered by hairs pure white to the skin. ”

“ Diagnosis.—Size large for the species; interorbital constriction near middle of frontal rather than anteriorly; supraorbital ridges of frontal concave laterally; skull large, strongly arched at base of rostrum; rostrum wide; nasals wide anteriorly; upper incisors wide, light yellow; molars large, tooth-rows long; zygomatic arches wide and heavy; interparietal short, wide, and posterior margin straight or with a slight posterior median angle.
Description.—Adults in dense unworn pelage taken in February at Two Buttes Reservoir: size large for the species ”

“ Type.—Mus. Nat. Hist., Univ. Kansas, no. 34417, young adult female, skin and skull; from eight miles northeast of Durango, 6200 feet, Durango, Mexico; collected 16 August 1949 by J. R. Alcorn, original number 10255.
Range.—Known only from the type locality.
Diagnosis.—Upper parts dark brownish gray (Smoke Brown, 16 A 2, to Biskra, 16 A 12) , darkest between ears; lower sides suffused with dull orange buff (13 H 9 to 12 H 9) ; dark eye ring and black spot at base of vibrissae conspicuous; ears 95 to 100 per cent as long as hind foot; bullae round, greatly inflated ”