308 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
A young specimen from Fort Reading is rather darker than usual on the hack, and may 
possibly belong to 8. douglassii. On account of the locality, however, I have entered it among 
the present species. 
The reception of many additional specimens, since the preceding description was written, 
substantiate the permanence of character as given above in the California animal, and as dis¬ 
tinguished from the 8. douglassii. These vary in the amount of hoary on the shoulders, hut 
in none is the hack darker than the ground color, and unbroken by mottling. The soles vary 
from entirely naked in summer skins, except immediately at the heel, to densely hairy to the 
tubercles in winter ones. Only in the latitude of San Diego do the soles appear to remain nearly 
naked throughout the year. 
This species was not recognized by Audubon and Bachman as any thing more than a variety 
of SpermopMlus douglassii . Even should this he the case, its name must take precedence of the 
last named species, on account of having been published first in the pages of the Fauna 
Boreali-Americana. 
This is the animal so well known in California, under the name of ground squirrel, as 
causing so much damage to the farmer by the depredations it commits on grain fields and, in 
fact, almost every agricultural product, as well as by the disturbances of the soil by its excava¬ 
tions. 
List of specimens. 
Catalogue number. 
Corresponding number 
of skull. 
| Sex and age. 
Locality. 
When 
collected. 
Whence and how 
obtained. 
Original number. 
Nature of 
specimen. 
Measurements. 
Collected by— 
From tip of nose to— 
Tail to 
end of— 
Length of hind ft. 
o 
>» 
K 
W 
Occip. 
Tail. 
> 
i 
K 
?2184 
Gila river. 
Dr. Antisell. 
Skull.... 
493 
San Diego, Cal, 
Lt. Trowbridge.... 
5.75 
7.00 
2.08 
A. Cassidy. t 
1597 
Dr. J. F. Hammond 
11.25 
8.00 
2.10 
1598 
Q 
.do. 
Dec. 29,1855 
5.12 
6.50 
1.93 
1599 
A 
11.50 
7.50 
1600 
o 
o 
• •••••.do.. 
Dec. 28,1855 
5.50 
6.75 
2.10 
468 
7599 
V 
Tejon Valley, Cal. 
Lt. R. S. Williamson 
B 
Mounted. 
7.25 
8.62 
2.10 
Dr. Heermann... 
467 
1398 
A 
2.01 
469 
■ ■ d n 
8.75 
2.15 
470 
10.75 
8.12 
9.75 
2.30 
.83 
.do. 
494 
Monterey, Cal. 
Lt.W. P. Trowbridge 
Skin .... 
6.75 
8.00 
2.06 
1181 
Santa Clara, Cal 
Dr. J. G. Cooper 
10.00 
7.00 
1 
2.10 
2384 
4.62 
5.87 
2.05 
608 
San Francisrn. 
R. D. Cutts. 
6.10 
7.40 
2.10 
606 
.do. 
..do. 
5.30 
7.00 
2 34 
433 
California. 
Philada. A. N. S... 
Mounted. 
5.87 
7.50 
2 38' 
Col. G. A. McCall. 
?865 
o 
Fort Reading, Cal 
Dr. J. F. Hammond. 
.... 
Skin .... 
3.75 
4.38 
1.65 
?2492 
o 
1 
In ale. .. 
.88 
1.75 
2.15 
6.30 
4.08 
2.00 
