740 
EXPLANATION OF THE PLATES. 
Page. 
Fig 3 —Putorius xanthogenys. —Yellow-cheeked weasel.—No. 536.—San Francisco.— 
Dried skin softened. 176 
a —ear. 
Fig. 4 —Putorius cicognanii .—Brown weasel.—Boston. 161 
a —side of head. 
Fig. 5 —Putorius frenatus. —Brownsville, Texas.—Half grown ; in alcohol. 173 
a —side of the head. 
Fig. 6 —Putorius richardsonii, Bon.—Illinois. . 164 
a —side of the head. 
Fig. 7 —Lutra canadensis, Sab.—Otter.—Washington, D. C.—Dried skin softened ; 
(skin of feet too much stretched). . 184 
a —side of head reduced one-half; b —muzzle from below ; c—left fore foot 
from below ; d —left hind foot from below, (half size.) 
Fig. 8 —Lutra californica, Gray.—California otter.—Cascade Mountains.—Dried skin 
softened, (feet shrivelled.),... 187 
a —muzzle from in front, (nat. size ;) b —left fore foot from below ; c—left 
hind foot from below, (half size.) 
PLATE XX. 
Fig. 1 —Sciurus douglassi, Bach.—No. 1265.—Upper des Chutes, Oregon Territory. — 
In alcohol. 275 
a —side of the head ; b —front view of head ; c —under surface of left fore 
foot; d —under surface of left hind foot. 
Fig. 2—? Tamias quadrivittatus .—Four-lined squirrel.—No. 1266.—Cascade Moun¬ 
tains, Oregon Territory ; lat. 44°.—Alcoholic specimen,. 297 
a —side of the head ; b —front view of head ; c—under surface of left fore 
foot; d —under surface of left hind foot. 
Fig. 3 —Spermophilus lateralis. —No. 1272.—Upper des Chutes.—In alcohol. 312 
a —side of the head; b —front view of head ; c—under surface of left fore 
foot; d —under surface of left hind foot. 
Fig. 4 —Aplodontia leporina, Rich.—Sewellel.—No. 966.—Astoria.—Dried skin soft¬ 
ened. 353 
a —front view of the muzzle ; b —ear ; c—under surface of left fore foot; 
d —under surface of left hind foot. 
Fig. 5— Perognatuspenicillatus, Woodhouse.—San Francisco Mountains, N. M. 418 
a —ear ; b —side view of tail, (from mounted specimen.) 
PLATE XXI. 
Fig. 1 —Dipodomys ordii, Woodhouse.—Monterey, Mexico.—In alcohol. 410 
a —side view of head ; b —under surface of head, with the jaw closed, show¬ 
ing the pouches and the hairy ante-chamher of the mouth ; c —jaws open, 
showing the interior of the mouth and the transverse ridges of the palate ; 
d —under surface of left fore foot; e—under surface of left hind foot; f— 
lateral view of a hind toe and claw. 
