492 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
of arched galleries of sticks and twigs, filled up with mule dung and moss, and from four to 
eight feet long, terminating usually in a bed of moss or hair under a rock. 
This spceies is readily distinguished from N. floridana, by its much smaller feet and rather 
more hairy tail, as well as by the much lighter color above and on the sides. The fur is longer, 
fuller and softer than in either N. floridana or N. micropus. There is no indication of the slate 
gray of N. micropus , and it has a more densely furred tail, which also appears longer. The 
feet, also, are even smaller than in N. micropus. Skull broader than in N. floridana. 
Since preparing the preceding article, a large number of specimens has been received, which 
tend to establish the species more fully. Among them are several from the Colorado river, 
collected by Mr. Schott, and three from the Pecos, collected by Capt. Pope. These are generally 
similar, except that one (No. 1730) is of a light grayish slate color, lined with darker. This 
is lighter than as described in N. micropus. I have not been able to examine the skulls, to see 
if they agree with the characteristics derived from the first specimens. 
A very good figure of this animal has been published in the Atlas of the Yoyage of the Yenus, 
taken from a specimen collected in Lower California by M. Neboux. This extends its distribu¬ 
tion from the Pecos river to the Gulf of California, and gives to it, compared with N. micro - 
pus, somewhat the same range as Spermophilus spilosoma, compared with 8. mexicanus. 
List of specimens. 
Catalogue number. 
fcD 
D« 
O 
O 
Sex and age. 
Locality. 
When col¬ 
lected. 
Whence and how 
obtained. 
| Original number. 
Nature of 
specimen. 
Measurements. 
Collected by— 
Nose to tail. 
s 
> 
o 
& 
j Tail to end of hairs. 
| Length of fore feet. 
| Length of hind feet.| 
Length of skull. 
| Width of skull. j 
Height of ear. 
289 
1674 
Chihuahua City.... 
John Potts. 
$kin. 
7.50 
.60 
1.18 
.85 
.84 
565 
Chevate Bprings, Sonora 
Dr. T. H. Webb.... 
. .do...... 
5.00 
.53 
1.17 
1033 
2201 
San Pedro river, Sonora. 
Major W. H. Emory 
Mounted. 
Dr. Kennerly. 
1328 
3 
Colorado bottom, Cal.. 
Mar. 31,1855 
.do. 
8 
Skin.,... 
10.50 
6.60 
6.85 
1.33 
1.00 
A. Schott.... 
1329 
2160 
Q 
April 4,1855 
.do. 
8 
, .do. 
9.00 
6.60 
1.30 
L.80 
.98 
.95 
....do. 
1339to ) 
1343* J 
1606 
San Diego, California 
Dr. J. F. Hammond 
Skin. 
7.00 
5.00 
.56 
1.18 
1.05 
? 1731 
3 
Pecos, New Mexico.... 
June 14, 1856 
Cant. J. Pone. 
8.00 
1.33 
1732 
Q 
May 12,1856 
..do. 
10.50 
4.90 
1.40 
1730 
3 
June 5,1856 
8.40 
1.33 
.70 
! 
, 
i Five young ones, belonging to 1329. 
NEOTOMA MICROPUS, Baird. 
Black Wood Rat. 
Neotwna mkropus, Baird, Pr. A. N. Sc. Phila. VII, April, 1855, 333. 
Sr. Ch.—A bove grayish slate, beneath with feet white. Feet small. Tail hardly two-thirds the length of body; scantily 
haired. Feet entirely white. 
This species is about the size of the Florida rat, Neotoma floridana , or a little larger, and 
belongs to the same section of slender tailed species. The head is broad and pointed, the 
whiskers longer than the head, mixed black and gray. The ears are very large, broad and 
