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MAMMALS OF MINNESOTA. 163 
the outer, are whiter, varying from grayish-white to pure white; 
the sides of body, especially anteriorly, are bright reddish fer- 
ruginous; the tail yellowish-rusty, with a sub-terminal border 
of black edged with yellowish.” The habitat assigned to this 
variety is the middle and southern portions of the Rocky moun- 
tains from near the northern boundary of the United States to 
New Mexico, westward to Pacific coast, eastward to the plains. 
It is quite difficult to decide to which of the nominal varieties | 
these specimens belong. They occur in the range of borealis, 
have the colors of quadrivitattus and size of pallidus. Asa 
matter of fact, very likely these varieties do not express all of 
the tendencies to variation which seem to be governed by the 
actually existing conditions of life rather than to express the 
genetic relations. 
The osteology of the Asiatic chipmunk would be of value 
only as taken together with a description of the entire anatomy 
and a minute comparison with other species of the genus, with 
a view to discover what relations exist between these closely 
allied species. A few measurements may prove instructive, as 
affording a means of comparison with T. striatus. 
Skull—length, 1.25 (7. striatus, 1.60), width,0.82 (0.97),nasals, 
0.38 (0.51), incisors, to palate, 0.65 (0.85),between molars, 0.20 
(0.24), rames, 0.80 (1,10). 
Shoulderblade, 0.60 (0.80), humerus, 0.70 (0.90), ulna, 0.88 
(1.00), longest metacarpal, 0.20 (0.28), pelvis, 0.85 (1.08), femur, 
0.95 (1.10), tibia, 1.10 (1.21), longest metatarsal, 0.50 (0.54). 
These figures indicate a much more slender skull in 7. stria- 
tus (1.46—1.64 being the width to length ratios approximately). 
This is largely due to the greater facial prolongation of the 
latter, in which the nasal bone is contained 3.18 times in the 
length of the skull, while in the smaller species it is 3.28 times. 
The humerus is shortest proportionally in 7. asiaticus (1.385 
and 1.22 being the proportions between humerus and femur in 
the two species.) Perhaps the shorter humerus may be corre- 
lated with less active and especially less arboreal habits. The 
T. asiaticus does not seem to burrow as extensively as our chip- 
munk. The greater length of the tail is as obvious in the 
skeleton as in the flesh. 
GENUS SPERMOPHILUS, F. Cuv. 
This genus, a synopsis of which is given beyond, contains 
about twenty species confined to the northern continents of 
