504 MONOGRAPHS-OF NORTH AMERICAN RODENTIA. 
My series of specimens does not suffice for a complete exposition of the 
variation in color of this species. In all, the lateral stripe is conspicuous, and 
the other characters differ little. I note, however, a decidedly richer tone 
in Mexican and Texan specimens than in those from Kansas and Nebraska. 
It is probable that the skull of this animal, when examined, will afford some 
specific characters, in size at least, if not in details of conformation. The 
venerable Dr. G. Lincecum, of Texas, lately deceased, has given notes on the 
habits of this species, in two special articles, below cited.* 
PEROGNATHUS PENICILLATUS, Woodh. 
Tuft-tailed Pocket-mouse. 
Perognathus penecillatus, Woonu.,t Proc. Acad. Nat. Sci. Phila. vi, 1853, 200 (San Francisco Mts., Arizona). 
Perognathus penicillatus, Woonu., Sitgreaves’s Rep. Expl. Zuni and Col. R. 153, 49, pl. 3.—LEC., Proe. 
Acad. Nat. Sci. Phila. 1853, 225 (mere mention).—Aup. & Bacu., Q. N. A. ili, 1854, 298 
(copied from Woodh.).—Bp., M. N. A, 1857, 418, pl. 20, f. 5. Gray, P. Z. S. 1868, 201 (wrong 
locality assigned) {—Cours, Am. Nat. i, 1867, 397 (Arizona)—Cours, Proc. Phila. Acad. 
1875, 287 (monographic).—Covrs & Yarrow, Zod]. Expl. W. 100 Merid. 1875, 110. 
Perognathus parvus, LECONT#, Pioc. Acad. Nat. Sci. Phila vi, 1853, 225 (in part. Not Cricetodipus parvus, 
Peale.) (The specimen noticed from the Colorado Desert is now before me; it is apparently 
avery young example of P. penicillatus.) 
Diacyosts.—About the size of Hesperomys leucopus. Tail vertebrze obvi- 
ously longer than head and body. Hind foot more than one-fourth the length 
of head and body. Tail crested above toward the end, and with long term- 
inal pencil of hairs. Soles distinctly naked to the heels, at least along a 
median strip. Antitragus distinctly lobed, with a sharp teat-like projection, 
opposite which is another smaller but distinct lobe of the tragus, the notch 
of the ear being defined by these two prominent points, the edge of the ear 
itself not bounding the notch at all. No appreciable fulvous stripe along the 
sides, where the color of the upper parts meets the white of the under parts 
without intervention of a third color. Above, “gray”—an intimate mixture of 
yellowish-gray with a dull grayish-brown; below, including whole fore leg, 
fore and hind feet, and inner aspect of thighs, white; tail bicolor—dark above, 
white below. Length about 3.25 inches (2.90-3 6); tail vertebre about 
4.00 (3.50-4.40), with a tuft half an inch or more longer. Soles about 0.95 
(0.90-1.00); ear above notch, 033 (0.30—0.35). 
*Pouched Rat. < Am. Nat. vi, 1572, pp. 369, 370. 
The Animals of Texas. < Amer. Sportsman (newspaper) of Feb. 28, 1874. 
t Special paper: “ Description of a new species of Perognathus, Wied.” < loe. cit., pp. 200, 201. 
tThe San Francisco Mountains are several hundred milis from San Francisco City, California, 
nearly in the middle of Arizona—formerly a part of New Mexico. The locality appears to puzzle some 
writers. 
