MAMMALS OF MINNESOTA. 209 
The single species thus far found under the genus Onychomys 
has differentiated into three more or less distinct geographi- 
cal races or varieties. Of these but one is found in Minnesota 
and that only upon the western boundary and a very short dis- 
tance east of it. 
The typical form is stated to be restricted to the upper Mis- 
souri river region, and is described as follows: 
‘Color above, grayish-brown, passing into yellowish-red, 
and finally into a stripe of fulvous on the sides. Feet, inclu 
ding outer surface of the forearm and under surface of the body 
and tail, white.”—Baird. 
‘- Beneath, snow-white; above, mouse-brown, with darker 
dorsal area. Tail twice the hind foot or less; much less than 
half the head and body. Fore foot more than half the hind 
foot. Ear about 0.50 high.”—Coues. 
‘«The chief distinguishing feature in coloration, as compared 
with Hesperomys leucopus, is the mostly white muzzle.—” Cowes. 
The following measurements from No. 7492 of the national 
museum, are selected as fairly illustrating the proportions: 
Nose to tail, 4.25; tail, 1.65; hind foot, 0.88; fore foot, 0.50; 
nose to eye, 0.60; nose to ear, 1.00; ear, 0.50. The skull of a 
somewhat smaller specimen measured 1.07 (Coues). 
Onychomys leucogaster var. torridus COUEs. 
Was founded upon a single alcoholic specimen from Arizona, 
which differs from the typical form of the species in having 
rather larger ears and tail and smaller fore feet. The colors 
are warmer. The following is Dr. Coues’ diagnosis : 
‘‘Beneath, tawny-white [?]; above brownish fulvous, with no 
darker dorsal area. Tail about two and a half times the hind 
foot ; almost half as long as head andbody. Fore foot half the 
hind foot. Ears about 0.75 high.”—Coues. 
Without discussing the characters on which this variety is 
founded, we may remark that in the only form which we have 
seen, the proportional length of the tail and limbs were found 
to be subject to considerable variation, and that even while the 
exact pattern of coloration was maintained. Coues gives the 
following measurements of the specimen described: ‘‘ Nose to 
tail, 8.75 ; tail, 2.00 ; hind foot, 0.80. fore foot, 0.40 ; nose to eye, 
0.50 ; nose to ear, 0.95; ear, 0.70. 
