268 U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
a slight degree; all the hairs, however, directed upwards, and forming a flattened pencil as 
long as the height of the ear. There is nothing of the woolly basal tufting of the eastern gray 
and fox-colored squirrels. The fur on the body is full and soft. 
The upper parts (about half the circumference of the body) with the sides of shoulders and 
thighs are of a finely grizzled bluish gray ; the hairs annulated subterminally with black, and 
tipped with a lighter shade than that at their bases. On the middle of the back is a distinct 
stripe of rich chestnut brown, about an inch wide, commencing at the shoulders (where, how¬ 
ever, it is illy defined) and extends to the root of the tail, (which it does not invade, however.) 
The under parts with the feet are white ; the colors of the belly and sides separated on the 
flanks by a distinct stripe of plumbeous black, about half an inch wide. The sides of the 
head are gray, the under surface is like the belly. The pencil of hairs on the ears is glossy 
black, tinged with chestnut at the base; the posterior hairs are almost entirely rich chestnut. 
The under surface, or under half of the tail, is pure white, the hairs without any annula- 
tion whatever except near the body; the hairs on the upper half are brownish white, with a 
basal and three other annulations of dark brown. The subterminal annulation, however, is 
broadest and black ; the ends of the hairs pure white. 
In the report of the Zoology of the Mexican Boundary Survey, I have described a Sciurus 
castanonotus, from the Coppermines of New Mexico, which, though similar in many respects, 
yet presents tangible differences. The most conspicuous is the entire absence of any indication 
of tufts. I am assured that these conditions are constant, all of the specimens in the San 
Francisco mountains exhibiting them and none of those at the Coppermines. The tail is less 
bushy; the upper hairs entirely black with white tips, or else white with a single median 
annulation of black. The wash of chestnut on the back is much broader, the lateral stripe 
less distinct. 
All these differences may, however, after all, be merely seasonal, or dependent on other 
causes, (although all the specimens in question were collected in winter,) and with a better know¬ 
ledge of the American species of squirrels now than when I first characterized the S. castano¬ 
notus (in 1855) I would hardly venture to impose a new name. As this has been done I 
retain it, and wait further evidence to verify or disprove what I have done. 
This species was first described by Dr. Woodhouse as 8. dorsalis, but finding the name pre¬ 
occupied by J. E. Gray for a species from Caraccas, (Pr. Zool. Soc. Lond. XYI, 1848, 138,) he 
changed it to the one it so worthily bears, of the liberal and enlightened head of the Topo¬ 
graphical Bureau, Colonel J. J. Abert. 
List of specimens. 
Catalogue number. 1 
Locality. 
When collected. 
Whence obtained. 
Nature of specimen. 
Measurements. 
Collected by— 
Nose to— 
Tail to end of— 
Length of— 
Height of ear 
anteriorly. 
Height above 
notch. 
Projection of 
tuft* 
Occip. 
Tail. 
Verteb. 
Hairs 
Fore ft. 
Hindft. 
2430 
San Francisco mts., 
N. M. 
Winter. 
Capt. L. Sitgreaves, 
U. S. A. 
Mounted. 
2.80 
11.00 
8. 
12. 
1.75 
2.70 
1.05 
1,42 
1.10 
Dr. S. W. Wood- 
house. 
