_Specimens examined._--Total, 31, from: 1 mi. N Agua Nueva, 5500 ft., 1; Domingo Cañon, Sierra Guadalupe, 6700 ft., 11 mi. S and 4 mi. W General Cepeda, 1; Carneros, 6800 ft., 6 (BSC); _1 mi. S Carneros, 6000 ft._, 4; 2 mi. W San Miguel, 5500 ft., 3; 8 mi. N La Ventura, 6000 ft., 10; La Ventura, 5600 ft, 6 (BSC).
+Cratogeomys castanops planifrons+ Nelson and Goldman
1934. _Cratogeomys castanops planifrons_ Nelson and Goldman, Proc. Biol. Soc. Washington, 47:146, June 13, type from Miquihuana, 5000 ft., Tamaulipas (listed, by mistake, as southern Nuevo León).
_Distribution._--Elevated montane valleys of Sierra Madre Oriental of extreme southeastern Coahuila, south and east into southwestern Nuevo León and Western Tamaulipas (see fig. 1).
_Remarks._--Specimens from Coahuila assigned to _planifrons_ compare favorably with topotypes of this subspecies although they are slightly larger in cranial dimensions (see tables 1 and 2). This small subspecies is darker and slightly larger than _subnubilus_ but in other ways is most closely related to _subnubilus_. _Cratogeomys c. planifrons_ shows little relation to other adjacent subspecies, including _tamaulipensis_, _subsimus_ and _rubellus_, all of which are considerably larger and paler.
_Cratogeomys castanops planifrons_ is found in both deep and shallow soils of the high, open valleys of the Sierra Madre Oriental; in Coahuila it was taken at elevations as low as 7200 feet and as high as 8700 feet.
_Specimens examined._--Total, 50, from: 4 mi. S and 6 mi. E Saltillo, 7500 ft, 7; 7 mi. S and 4 mi. E Bella Union, 7200 ft., 14; _12 mi. W San Antonio de las Alazanas_, 16; _12 mi. S and 2 mi. E Arteaga, 7500 ft._, 11; 2 mi. E and 2 mi. N San Antonio de las Alazanas, 8700 ft, 2.
Emphasis Notation: _text_ - italicized +text+ - bold ~text~ - small caps
Possible Typos Corrected Aquanaval => Aguanaval
End of the Project Gutenberg EBook of Geographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila Mexico, by Robert J. Russell and Rollin H. Baker