e same times of the year have
been compared for color of pelage. Capitalized color terms are those
of Ridgway, Color Standards and Color Nomenclature, Washington, D. C.,
1912. Specimens made available through the courtesy of the authorities
of the Biological Surveys Collection of the United States National
Museum are indicated in the accounts of subspecies as BSC; other
specimens listed are in the collection of the University of Kansas
Museum of Natural History. Assistance with field work is acknowledged
from the Kansas University Endowment Association and the National
Science Foundation.

In any one of the lists of "Specimens examined" beyond, the order of
arrangement of the localities is from north to south. Those localities
listed in Roman type are represented on the distribution map (Figure
1) by blacked-in circles. Each of several circles covers two or more
localities because the localities are close together. In any such
instance the northernmost place is listed in Roman type and the names
of the other places follow in Italic type. Measurements in millimeters
are given in table 1 for females and in table 2 for males.

+Cratogeomys castanops convexus+ Nelson and Goldman

1934. _Cratogeomys castanops convexus_ Nelson and Goldman, Proc. Biol.
Soc. Washington, 47:142, June 13, type from 7 mi. E Las Vacas
[= Villa Acuna], Rio Grande Valley, Coahuila (opposite Del Rio,
Texas).

_Distribution._--Extreme northern Coahuila, east and north of the
Serranias del Burro (see fig. 1).

_Diagnosis._--Previously known from only one specimen, a subadult
female, this subspecies has not been well diagnosed. At hand we have
five near topotypes of _convexus_ (including two adult females and one
adult male) and specimens assignable to this subspecies from several
other localities. This subspecies may be characterized as follows:
Size medium (see tables 1 and 2); dorsal profile of skull convex in
females and flat, especially posteriorly, in males; zygomata weakly
constructed and not widely flaring; mastoid and tympanic bullae
inflated; nasals short; rostrum broad and short; maxillary teeth
large.

[Illustration: ~Fig. 1.~ Geographic ranges of the subspecies of
_Cratogeomys castanops_ found in Coahuila, Mexico.

Guide to subspecies 4. _C. c. bullatus_ 8. _C. c. subsimus_
1. _C. c. convexus_ 5. _C. c. ustulatus_ 9. _C. c. goldmani_
2. _C. c. consitus_ 6. _C. c. jucundus_ 10. _C. c. subnubilus_
3. _