EXPLANATION OF THE PLATES. 
Fig. 2—Arvicola montana, Peale.—No. 1271.—Lost river, California.—In alcohol... 
a—side view of head ; b—front view of head ; c—front face of upper in- 
cisors ; d—under surface of left fore foot ; e—under surface of left hind 
foot, (twice nat. size.) 
Fig. 3—Perognatus flavus, Baird.—Missouri river, above Yellow Stone.—In alcohol... 
a—side view of head ; 6—under surface of head, with jaws closed ; c—under 
surface of head, with jaws open, showing the roof of the palate, with its 
transverse ridges ; d—under surface of left fore foot ; e—under surface of 
left hind foot. 
Fig. 4—WNeotoma occidentalis, Cooper.—No. 968.—Astoria, 0. T.—Dried skin softened 
a—side of left ear; b—under side of left fore foot ; c—side view of toe of 
left fore foot ; d—under surface of left hind foot; e—side view of toe of 
left hind foot. 
Fig. 5—Jaculus hudsonius.—Jumping mouse —Carlisle, Pa.—In alcohol ; twice mag- 
a—side of left ear ; B—under surface of muzzle ; c—under side of left fore 
foot ; d—under side of left hind foot. 
PLATE XXII. 
Fig. 1—Geomys bursarius.—Gopher.—St. Louis.—In alcohol..........cccceceeceeeeseeececees 
a—side view of head; b—under surface of head, with the jaws closed, 
showing the pouches; c—under surface of ‘head, with the jaws open, 
showing the tongue, the hairy ante-chamber of the mouth, and the 
naked space behind the incisors; d—under surface of head, with lower 
jaw removed, showing the belt of hair across the palate, the naked space 
between this and the incisors, the naked portion of the palate, with its 
ridges, and the upper molars ; e—under surface of the left foot ; f—under 
view of middle claw of left fore foot ; g—side view of the same ; h—under 
surface of left hind foot. 
Fig. 2—? Thomomys borealis.—No. 1260.—Canoe creek, Cal.—In alcohol.............0068 
a—side view of head ; /—under surface of head ; c—under surface of left fore 
foot; d—side view of its middle claw; e—under-surface of left hind foot. 
Fig. 3—Geomys pinetis, Raf.—Gopher.—F lorida.—Dried skin softened..............s00008 
a—under surface of left fore foot; b—side view of its middle claw; c— 
under view of its middle claw ; d—under view of left hind foot ; e—front 
view of upper incisors, showing the single median groove. 
Fig. 4—Geomys hispidus, Lec.—Mexico.—Dried skin softened........ccecscssccsececsecseeeee 
a—under surface of left fore foot; b—side view of its middle claw; c— 
under surface of the same; d—under surface of left hind foot. 
PLATE XXIII. 
Fig, 1— Cervus macrotis, Say.—Mule deer, female.—No. 1200.—Upper Des Chutes, 
a—side view, and 6—under surface of left fore foot ; c—side view, and d— 
under surface of hind foot. 
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