SCIURIDAI—TAMIAS ASIATICUS AND VARIETIES: 797 
that ver. pallidus does to var. quadrivittatus—a light gray form, in which all 
the dorsal stripes, except the central one, are nearly obsolete. I have yet to 
see a specimen in which there are not faint indications of the others. The 
specimens thus far known are nearly all from the desert region adjoining 
the Gila River. 
Hapirat.—Southwestern New Mexico and adjoining portions of Arizona 
and Nevada. 
GENERAL REMARKS ON TAMIAS ASIATICUS AND ITS VARIETIES. 
DirFERENTIAL CHARACTERS.—As already noticed under the head of T. 
striatus, the present species finds its nearest ally in 7. striatus. In size, there 
is little difference between the larger varieties of T. asiaticus and T. striatus, 
the latter averaging rather the larger than any form of the former. The 
longer tail, different. coloration, and presence of two upper premolars in 7. 
asiaticus, as compared with T. striatus, serve at once to distinguish the two 
species. TT. asiaticus differs too widely from either T. lateralis or T. harrisi 
to render a comparison with them necessary. 
While the five varieties of 7. asiaticus above characterized so thoroughly 
intergrade that they are not to be trenchantly defined, the extreme’ phases of 
differentiation are often quite widely diverse, and would require recognition 
as distinct species were they not found to be so inseparably connected. The 
extremes of the series in size as in color are vars. pallidus and townsendi, and 
are developed where the conditions of environment are the most diverse. 
Specimens from the same locality, of either variety, differ very considerably 
in color, and sometimes agree quite closely in this respect with the average 
type from a quite distant region. Thus, occasionally, specimens are met with 
in the wooded mountainous districts of Colorado that closely approach the 
pale form of the open arid plains. As will be seen from the subjoined lists 
of specimens, a considerable portion of the specimens I have had before me 
are as well referable to one variety as to another. These, as a rule, come 
from regions intermediate to the localities where the several forms above 
recognized reach respectively their greatest degree of differentiation. 
Specimens from the northern portions of the continent are almost 
indistinguishable from others from Siberia. The two examples of the Sibe- 
rian animal I have had an opportunity of examining correspond in every 
detail with examples from the Mackenzie River district and other northern 
