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_Remarks._--_Cratogeomys castanops subsimus_ is the largest known
subspecies of the species in cranial dimensions, but is exceeded in
size of body by _C. c. jucundus_ to the north. Of adjacent subspecies,
_subsimus_ is the most closely related to _excelsus_ and shows little
or no relationship to the smaller and darker _C. c. subnubilus_ and
_C. c. planifrons_, which are found at higher elevations to the south
and southeast, respectively. Movements by _subsimus_ to the north,
east, and south are barred by inhospitable mountains. Specimens of
_subsimus_ from the northeastern part of its range are larger and
darker than other specimens assigned to this subspecies. An adult
female, assigned to _subsimus_, from the vicinity of Santa Rosa is
noticeably smaller and paler than typical specimens of this
subspecies.

_Cratogeomys castanops subsimus_ occurs in scattered colonies in
sandy soils principally in the upper drainage of the Rio Salinas.
Specimens have also been taken from the foothills of the Sierra
Madre Oriental and westward on the elevated desert plains.

_Specimens examined._--Total, 22, from: 3 mi. S and 3 mi. E Muralla,
3800 ft., 3; 2 mi. N Santa Cruz, 2; 21 mi. S and 11 mi. E Australia,
4400 ft., 6; Jaral, 3860 ft., 4 (BSC); _Hacienda El Tulillo, 5 km. S
Hipolito_, 2; 17 mi. N and 8 mi. W Saltillo, 5200 ft., 1; 3 mi. N and
5 mi. W La Rosa, 3600 ft., 1; 12 mi. N and 10 mi. E Parras, 5000 ft.,
1; N foot Sierra Guadalupe, 9 mi. S and 5 mi. W General Cepeda, 6200
ft., 1; _N foot Sierra Guadalupe, 10 mi. S and 5 mi. W General Cepeda,
6500 ft._, 1.

+Cratogeomys castanops goldmani+ Merriam

1895. _Cratogeomys castanops goldmani_ Merriam, N. Amer. Fauna 8:160,
January 31, type from Canitas, Zacatecas.

_Distribution._--Plains of northeastern Zacatecas, northward into
extreme southwestern Coahuila (see fig. 1).

_Comparisons._--Compared with _Cratogeomys castanops subnubilus_,
found to the east, _goldmani_ differs in: Body larger, tail and hind
foot longer; color paler, more rufous and less blackish; skull larger;
zygomata more widely flaring; palate larger; rostrum broader; nasals
longer; maxillary teeth larger. Compared with _Cratogeomys castanops
rubellus_ Nelson and Goldman, found to the southeast, _goldmani_
differs in: Body and skull smaller; zygomata less widely flaring;
palate shorter; rostrum narrower; maxillary teeth smaller.

_Remarks._--Records of