_Reithrodontomys saturatus_ Allen and Chapman, Bull. Amer.
Mus. Nat. Hist., 9:201, June 16, 1897, type from Las Vigas,
Veracruz.
_Reithrodontomys megalotis saturatus_, Howell, N. Amer. Fauna,
36:36, June 5, 1914.
_Range._--Northeastern part of state.
_Specimens examined_, 12: nos. 100202-100212, 100273, from 1 mi. N
Zamora, 5,450 ft.
_Remarks._--Howell (1914:37) referred nine specimens from Nahuatzin to
this race and two from the same place to the subspecies _R. m.
zacatecae_. Our specimens from Zamora agree with topotypes of _R. m.
saturatus_ and with specimens of that subspecies from the Valley of
MA(C)xico in dark color and large size.
If our specimens of _Reithrodontomys megalotis_ are correctly
identified, subspecifically, _R. m. zacatecae_ ranges southward around
the western end of the geographic range of _R. m. saturatus_.
Where _R. megalotis_ and _R. fulvescens_ occur together, we find the
skull of the latter to be distinguishable by: a median spine on the
posterior border of the hard palate (truncate in _R. megalotis_); an
S-shaped instead of a C-shaped pattern on the worn occlusal face of
the last lower molar; and two re-entrant angles, on the lateral side
on the worn occlusal surface of the third upper molar, reaching
halfway across the tooth whereas in _R. megalotis_ the anterior
re-entrant angle is wanting or extends less than a third of the way
across the crown surface of the tooth.
=Reithrodontomys megalotis zacatecae= Merriam