RODENTIA—GEOMYINAE—GEOMYS CASTANOPS. 385 
fectly symmetrical in size and shape. The external ears are entirely obselete, with scarcely a 
thickened ridge of skin to represent the auricle. The tail is contained not quite three times in 
the body ; it is moderately clothed with stiff appressed hairs of a dusky color. 
The fur is quite sparse though moderately soft everywhere. The cheek pouches are small 
and not very capacious ; scantily haired within. 
The fore feet are decidedly shorter than the hinder ones; its claws are moderately large and 
stout, acuminate near the tips. The third claw, as measured above, does not reach nearly from 
the end of its digit to the tubercle on the palm ; below, it is scarcely one-third the total length 
of the hand. From the heel to the end of the first claw is about two-fifths of the whole hand. 
The second and fourth fingers and claws are of the same length, or the second finger is even 
the longer ; the fourth claw, as usual, is, however, the stouter. The first claw does not quite 
reach the end of the fifth finger ; the fifth claw barely to the end of the fourth finger. On the 
hind foot the toes are cleft quite deeply; the first is longer than the fifth (the claw of the 
latter reaching to the middle of the claw of the former) ; the second claw reaches nearly to the 
end of the third, and is even the longer, besides being very broad and spoon-shaped ; the fourth 
claw reaches to the end of the second toe. 
The upper parts and sides, generally, are of a pale brownish yellow ; the hairs on the back 
and thighs slightly tipped with darker yellowish brown, so as to impart a faint shade of this 
color ; the sides and under parts are rather paler, showing a good deal of the dark plumbeous 
bases to the hairs. The top, anteriorly, and the sides of the head, are of a pale yellowish 
chestnut ; this color extending behind the ears in a symmetrical subcircular patch, having the 
ear as a centre, and a radius of about three-quarters of an inch. These patches are distinctly 
and sharply defined ; the two on opposite sides separated by a narrow strait, colored like the 
back. The chin, pouches, and throat are somewhat of the same color, with a few dusky hairs. 
The region immediately around the ears is rather dusky. 
The only specimen of this species, at present known to naturalists, is the one in the Patent 
Office, which served as the basis of my description in Captain Stansbury’s report. It was col- 
lected by Lieut. James W. Abert, United States army, and is labelled as having been obtained 
on the prairie road to Bent’s Fort, New Mexico. 
* 
General dimensions. Inches. | Lines. 
NORE NOLCYOSe asec cane soe ann canebaacanes a 4 
CBR ol Sena apes ae ae eee al 7 
root Of tall’: st 2, Joon ace cen een nan 7 3 
Tail 2 5263 eR 2558 oS Soe cae 2 2 
ars width: 23 300632 Sore ee eee ae | wears tee 2 
Arm ; fore foot to end of claws ---.----------- 1 4 
longest liwe-se= see ee ase eee ae eee |p ear 6 
hand, without claw .....----.. ..--..-|-------- 10} 
third finger, without claw...-...----..-|-------- 3} 
BECONON GHW eee a aaa ae een ead 4} 
: Lien ee ae ee el eee 24 
Leg; hind foot, from heel to end of claws----- 1 54 
LOT EGG eee as ae aa ee a | Spa 3 
49 L 
