1904. _Peromyscus melanophrys consobrinus_ Osgood, Proc.
Biol. Soc. Washington, 17:66, March 21, type from
Berriozabal, Zacatecas.
_Distribution in Tamaulipas._--Mexican Plateau part of
state.
A lactating female caught on July 20 and four males from Miquihuana
weighed, respectively, 51, and 50.2 (47-54) grams. A female, taken on
July 24, 14 miles north and six miles west of Palmillas in a valley
covered by mesquite and other bushes, had 3 embryos 10 mm. in
crown-rump length, and weighed 60 grams. One specimen from nine miles
southwest of Tula was caught in an outcrop of rocks and two others were
taken among bushes on the desert. A female on October 10 carried 4
embryos 2 mm. in crown-rump length.
Specimens of _P. melanophrys_ here listed are the first to be reported
from Tamaulipas. They are assigned to the subspecies _consobrinus_ on
the basis of dark color and because their size closely corresponds to
that of the holotype. The specimen from the vicinity of Palmillas and
one from Miquihuana (56408) are larger than the others and grayish.
A specimen (56413) from Miquihuana lacks all the molariform teeth. Its
alveoli in one maxilla are closed and those in the opposite maxilla are
more open than is normal.
_Measurements._--Average and extreme measurements of four
males, two females (56413, 56408) from Miquihuana, and a
female (56414) from 14 miles north and 6 miles west of
Palmillas, are, respectively, as follows: total length (two
males only), 249, 245, 265, 247, 280; length of tail
vertebrae (two males only), 137, 134, 141, 131, 157; length
of hind foot, 26.7 (26-27), 27, 27, 27; ear from notch, 23.7
(23-24), 25, 24, 25; greatest length of skull, 30.3
(29.5-31.0), 31.2, 31.8, 32.2; interorbital constriction,
4.8 (4.7-4.9), 4.9, 4.8, 5.0; length of palatine slits, 6.6
(6.2-6.8), 6.9, 6.9, 6.8; length of diastema, 8.1 (8.0-8.3),
--, 8.5, 8.5; alveolar length of maxillary tooth-row, 4.5
(4.3-4.7), --, 4.3, 4.6.
_Records of occurrence._--Specimens examined, 16:
Miquihuana, 6200 ft., 6; 14 mi. N, 6 mi. W Palmillas, 5500
ft., 1; Nicolas, 56 km. NW Tula, 5500 ft., 6; 9 mi. SW Tula,
3900 ft., 3.
=Peromyscus difficilis petricola= Hoffmeister and de la Torre