ZOOLOGY—MAMMALS. 
99 
CYNOMYS LUDOVICIANUS. 
Missouri Prairie Dog. 
Arctomys ludovicianus, Ord, Guthrie’s Geog. 2d Am. Ed. II, 1815, 292, 302. 
Sptrmophilus ludovicianus, “ Lesson, Manual, 244, 658.” 
F. Cuvier, Suppl. Buffon, I, Mam. 1831, 316. 
Aud. & Bach. N. Am. Quad. II. 1851, 319 ; pi. xcix. 
Cynomys ludovicianus, Baird, Gen. Rep. Mammals, 1857, 331. 
Size of fox squirrel, Sc. vulpinus, but heavier ; ears very short, not projecting above fur. Tail short, with the hairs, about 
one-third the length of body. Claws long, very stout; the thumb of fore feet armed with -a long claw instead of a flat nail. 
Soles with a patch of hair. Color above, reddish brown or cinnamon, with the tips of the hairs lighter and with scattered black 
hairs interspersed ; beneath, brownish white or yellow. In winter of a more grayish cast above. Hairs on the upper part lead 
color at base, then pale cinnamon white to cinnamon. Tail like the back, its tip black, with the hair light colored at base- 
Length about 12 inches ; tail, with hairs, 4 inches ; hind foot about 2.25 inches. 
Upper Missouri. 
ARCTOMYS FL AVI VENTER, Bachman. 
Yellow-Footed Marmot. 
Arctomys flaviventer, Aud. & Bach. Pr. A. N. Sc. Phila. I, 1841.— Ib J. A. N. Sc. Phila. VIII, ii, 1842, 309.— 1b. N. 
Am. Quad. Ill, 1853, 160 ; pi. cxxxiv. 
Baird, Gen. Rep. Mammals, 1857, 343. 
Sp. Ch.—S ize ol common woodchuck. Above, yellowish brown, somewhat grizzled with gray. Under parts of body and 
tail, and the legs all round, inside andj ut, reddis chestnut. 
This specimen, (60) an adult female, was obtained on the north side of the Columbia, opposite 
Fort Dalles, May 20, 1855; is not found, so say the Indians, on the south side of the river, at 
least in the vicinity of Fort Dalles. They prefer rocky places ; utter a shrill chirp or whistle 
when discovered. 
Measurement of specimen No. 60, procured May 19, 1855. 
Length from tip of snout to insertion of tail. 
insertion of tail to tip of caudal vertebras 
end of vertebras to tip of hair. 
hand to end of longest claw. 
heel “ “ “ . 
tip of nose to angle of eye. 
Inches. 
Lines. 
14 
9 
4 
6 
2 
0 
1 
7 
2 
10 
1 
6 
Iris, hazel; muzzle and chin, hair short, grayish white. Hairs on crown of head, brown, some 
tipped with whitish. Scattering long black hairs are found interspersed. Fur on hack of the 
neck, blackish brown at the base for ^ an inch, then foxy, then dark brown, the greater por¬ 
tions are tipped with white, these white ends being of irregular length, a few are tipped with 
brownish black. 
Hair on anterior portion of back, shorter as if worn off. Hairs of posterior portion of back 
similar to those of the neck, except that the brown is lighter and the general appearance more 
ferruginous. Fur of breast, shoulders, fore arm, inside of thighs, legs, and belly, foxy yellow, 
with lighter tips and darker bases in many situations. Soles of feet black. Tail, reddish brown 
above, some of the hairs near the insertion tipped with whitish. Under surface of tail darker. 
Posterior surface of ear sparsely covered with short grayish white hairs. The edges of the ears 
are black. 
A light band in front of the eyes from lore to lore. Teeth white. 
