ttes, Colorado, and south to Clayton, New
Mexico. The extent of the range to the southwest in New Mexico
has not been determined.

_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;
tail approximately 76 per cent as long as head and body; hind
feet of medium length. Pelage: moderately long, thick; tail
covered with short hairs; longest vibrissae 80 mm. Color:
sides near Raffia (11 E 6) (capitalized color names and
designators are of Maerz and Paul, A Dictionary of Color,
McGraw-Hill Book Co., New York, 1930) overlaid with black, the
general effect being grayish buff (13 G 6); back darker,
moderately to heavily overlaid with black; indistinct dark eye
ring; underparts whitish, fur basally gray except patch of fur
pure white to base almost always present on upper throat; dark
line around mouth; tail bicolor, black above, whitish below;
feet white to ankles.

Skull: large for the species, strongly arched at base of
rostrum; rostrum heavy; zygomatic arches widely spreading,
heavy, squarish; braincase moderately ridged and angular;
nasals wide anteriorly, lateral margins nearly parallel or
converging evenly posteriorly, tapered abruptly at posterior
ends which reach posteriorly beyond anterior plane of orbits;
dorsal branches of premaxillae extending 0.5 to 1.2 mm.
posterior to nasals; interorbital region moderately channeled,
narrowly constricted near middle of frontal (instead of
anteriorly); supraorbital ridges concave laterally, diverging
more strongly posterior to interorbital constriction (frontal
8.7 to 9.5 mm. wide at posterior ends of supraorbital ridges);
temporal ridges widely flaring on parietals; occipital ridges
prominent; interparietal broadly rectangular between temporal
ridges, usually short in median line