maxillary tooth-row, 9.2; length of
incisive foramina, 9.7; length of palatal bridge, 8.9.

_Remarks._--The large size and distinctive cranial characters
of _N. m. scopulorum_ are fairly constant in the northeastern
part of its range, but there is a wide range of variation in
color. The only two skins from the type locality differ
markedly in color. Both specimens (the type and KU 37138,
adult male) were collected on 16 May 1950 and are in
moderately worn pelage. The upper parts of the holotype are
much more yellowish than in KU 37138, and are even lighter
buff than adults in unworn pelage from Two Buttes. The
underparts of the holotype are more extensively white than in
almost any other specimen seen of _Neotoma mexicana_. 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. The dark line around the mouth is present, as usual for
the species. The upper parts of KU 37138 are like those of the
adult in worn pelage from Two Buttes peak, described above;
the underparts have only small patches of pure white fur on
the throat and inguinal region, being elsewhere gray at the
base of the fur, as is usual for the species.

The molars of the type specimen are in an advanced state of
wear, having the pattern of the enamel folds still discernible
but the depth of remaining enamel slight. A large alveolar
abscess surrounds the abnormal left M1. There are two, much
worn, peglike fragments of the tooth projecting slightly from
an ovoid alveolar cavity 5.1 mm. long and 4.3 mm. wide. As a
result of the reduction of wear on the opposing m1, the crown
of m1 is much less worn than those of the other lower molars
and projects 0.8 mm. above the occlusal level of the two
posterior molars. A few barbed cactus glochids (bristles) are
inbedded in the cavity around the base of the molar remnants.
Although glochids are of rather frequent and normal occurrence
between the teeth of _Neotoma albigula_ and _N. micropus_,
they are not so commonly found in _N. mexicana_ and possibly
induced the alveolar infecti