Western Woodchuck 145 
a. Fore feet with four clawed digits; pollex indistinct, with a 
flat nail; molar series running parallel. Marmota, p. 145 
b. Fore feet with five clawed digits; molar series converging 
behind. Cynomys, p. 148 
B. Tails usually long; at least more than i the total length. 
a. Tail hairy, but not bushy, rather shorter than in b; ears 
never tufted and internal cheek pouches always present, 
a'. Back with a series of five dark and four longitudinal lines. 
Eutamias, p. 170 
b'. Back with two black stripes enclosing a white one on 
each side. Callospermophilus, p. 166 
c'. Back with one white stripe on either side. 
Ammospermophilus, p. 164 
d'. Pattern of markings various, but never as in preceding 
genera. Citellus, p. 1 55 
b. Tail long, very broad and bushy; ears pointed, and often 
tufted ; no cheek pouches. Sciurus, p. 181 
Genus MARMOTA (from marmot, Dutch name of European species) 
Marmota Frisch, Nat. Syst. vierfuss. Thieve., pi. 9 (1775). Type 
M. alpina. 
Form stout and heavy, ears and tail short, the latter about one 
quarter of total length; cheek pouches very small; fore feet with 
four clawed digits, pollex rudimentary with a flat nail ; skull heavy, 
postorbital processes well developed, broad at the base, decurved 
and directed at right angles to the axis of the skull; dentition, 
i. \; pm. f; m. f X 2 = 22; incisors broad and strong; molars 
with only two transverse grooves, in two nearly parallel series hardly 
converging at all posteriorly; anterior upper premolar nearly as 
large as the other one. 
This genus, containing the animals known as Woodchucks 
in America and as Marmots in the Old World, is found 
throughout the northern and mountainous regions of the 
Old and New Worlds. Only one out of some six described 
American species has been met with in Colorado. 
Marmota flaviventer (Lsitflavus, yellow, + venter, belly, 
yellow-bellied). Western Woodchuck. 
Arctomys flaviventer Aud. and Bach., Proc. Acad. Nat. Sci. Phila., 
p. 99 (1841). 
Type locality. — ' ' Mountains between Texas and California." 
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