unnamed subspecies which may be described and
named as follows:

#Thomomys talpoides meritus# new subspecies

_Type._--Male, adult, skull and skin, no. 25628 Mus. Nat. Hist.
Univ. Kansas; from 8 mi. N and 19-1/2 mi. E Savery, 8800 ft.,
Carbon County, Wyoming; obtained on July 19, 1948, by George M.
Newton; original no. 4.

_Range._--Sierra Madre Mountain Range of southern Wyoming and
northern Colorado.

_Diagnosis._--Size small (see measurements); color dark,
upperparts in worn pelage of July darker than (near, _n_) Raw
Umber (capitalized terms are of Ridgway, Color Standards and
Color Nomenclature, Washington, D. C., 1912) and in fresh pelage
of August between (near, 16') Prout's Brown and Mummy Brown;
skull small; relative to basilar length, skull narrow across
rostrum, zygomata and mastoids; nasals short and posteriorly
truncate; premaxillae extending behind nasals; temporal lines
faint and divergent posteriorly.

_Comparisons._--From _Thomomys talpoides rostralis_ (North
Platte River Valley, SW of Saratoga, Wyoming), the subspecies to
the east and south, _T. t. meritus_ differs in: Lesser size,
darker color, smaller and slenderer skull. The slenderness is
especially noticeable in the breadth across the zygomata,
mastoids, and rostrum. From _Thomomys talpoides clusius_
(topotypes), the subspecies to the north and west, _T. t.
meritus_ differs in: Color much darker; rostrum longer; skull
narrower across mastoids and zygomata; tympanic, and also
mastoid, bullae smaller. Resemblance to _T. t. clusius_ is shown
in the narrowness of the skull interorbitally and in the
shortness of the tooth-row.

_Remarks._--The specimens of _Thomomys_ from Wyoming on which the name
_T. t. meritus_ is based were obtained by Mr. E. Lendell Cockrum and his
associates with the thought that intergradation might be shown between
_T. t. rostralis_ to the east and _T. t. clusius_ to the west. The
animals showed instead, that there was a subspecies differing from
each of the two mentioned subspecies in small size, dark color and
slenderness of skull. Acknowledgment of assistance with field work is
made to the Kansas University Endowment Association.

_Measurements._--Average and extreme measurements of seven adult
males and five adult females, from the type locality, are as
follows: Total length, [Male]