. S, 2 mi. E Eagle Nest, 8100 ft., 21;
Taos Mountains, east slope, 8800 ft., 1 (USBS); _Coyote Creek_, 1
(USBS).

Microtus pennsylvanicus uligocola new subspecies

_Type._--Adult male, skin and skull, number 26898, University of
Kansas, Museum of Natural History, obtained by James O. Lounquist,
original number 349, 6 miles west and 1/2 mile south of Loveland,
5200 ft., Larimer Co., Colorado, on July 26, 1948.

_Range._--Northern Colorado. See Figure 2 and list of specimens
examined.

_Diagnosis._--Entire animal and skull large; color average for the
species, neither extremely pale or dark in summer pelage; molar
tooth-row long; nasals narrow; maxillary septum large; first upper
molar wide; anterior margin of zygomatic arch above infraorbital
foramen not deeply indented; fenestrae in posterodorsal parts of
squamosal bones relatively long; braincase not elongate; auditory
bullae and meatus large.

_Comparisons._--From _M. p. modestus_, _M. p. uligocola_ differs as
follows: averages paler; prelambdoidal breadth and alveolar length
of molar tooth-row significantly greater. Six pairs of skulls were
compared. Of the features listed above under the "method of pairs"
only two features differed in more than 75 per cent of the pairs;
in 5 of 6 pairs _uligocola_ had a less distinctly indented anterior
margin of the zygomatic arch (Confidence Limit .95) and a more
elongate posterodorsal squamosal fenestra (C. L. .85). Seven pairs
of skulls from Boulder, Colorado, representing _uligocola_ and from
Colfax County, New Mexico, representing _modestus_ differed in more
than 75 per cent of the pairs in three features. Only one of these
differences, the elongation of the posterodorsal squamosal
fenestra, was the same as a difference noted above between
topotypes of _uligocola_ and _modestus_. A comparison of ten pairs
of skulls of _uligocola_ from Boulder, Colorado, and topotypes of
_uligocola_ revealed no significant differences. These observations
are indicative of 1) the differences between samples and
populations which may be assigned to a single subspecies, and 2)
the fact that in general these local differences are less than the
differences between subspecies. From _insperatus_, the subspecies
to the north, _uligocola_ differs as follows: darker in both summer
and winter pelage; a