olima, Jalisco, _C. g. tellus_ differs in: Hind
foot smaller; color paler brownish above in contrast to
glossy black, creamy-white below rather than buffy, feet
clothed with whitish instead of brownish hairs; skull larger
(basilar length averaging 55.3 in females compared with
53.2, no males available for comparisons); zygomatic breadth
less; nasals longer, extending posterior to front edge of
anterior roots of zygomata rather than ending even with, or
slightly behind, them; rostrum more massive; mastoid
processes of squamosal larger; paroccipital processes
extending farther laterally; upper incisors projecting
anteriorly, rather than recurved; maxillary teeth larger
(length of maxillary tooth-row averaging 14.6 compared with
13.3).

Close comparison with _C. g. imparilis_ from Patzcuaro,
Michoacan, is not needed, _but C. g. tellus_ differs
especially in: Color of underparts and hairs of feet whitish
rather than brownish; skull smaller; zygomatic breadth
greater; interorbital constriction broader; nasals longer;
maxillary tooth-row longer.

_Measurements._--Averages of three adult females, including
type, and the measurements of an adult male (in parentheses)
from the type locality are: Total length, 338 (356); length
of tail, 92 (87); length of hind foot, 45 (47);
occipitonasal length of skull, 64.1 (68.7); basilar length,
55.3 (61.4); zygomatic breadth, 42.7 (48.0); interorbital
breadth, 9.6 (11.4); greatest height of cranium, taken from
palate perpendicular to line touching two highest points on
top of skull, 23.9 (25.3); least depth of rostrum, 10.6
(11.7); breadth of rostrum, 14.7 (16.5); length of nasals,
23.6 (25.2); width across mastoid processes of squamosal,
43.8 (49.7); height of occiput, 18.1 (19.9); length of
maxillary tooth-row, 14.6 (15.2).

_Remarks._--The distribution of _C. gymnurus_ is spotty; its
occurrence seemingly depends on edaphic conditions. The
isolation of soils with textures suitable to this animal has
resulted in the isolation of gopher populations. The
distribution is similar to that of species occurring on
islands. In this instance, however, the populations of
gophers are separated by soils of heavy texture which render
burrowing difficult or impossible for gophers. Such
condition