SACCOMYID.H—PEROGNATHIDINZ—P. MONTICOLA. 5O9 
- which embraces Arizona and the contiguous part of California on “the oppo- 
site side of the river. Specimens are rare; there may be none whatever in 
Europe. Woodhouse, LeConte, Baird, and myself are possibly the only nat- 
uralists who speak of the species from autoptical examination. 
The relationships of some allied species being considered under other 
heads, the only point here arising for discussion relates to the “ Cricetodipus 
parous” of LeConte, 7c. The specimen upon which that writer based his 
remarks is now before me. It is not adult, as supposed, but very young and 
ungrown, as shown by the unworn state of the teeth; although the tail is not 
crested, there are indications that it would have become so; the relative pro- 
portions and coloration are exactly as in P. penicillatus, to which I have little 
hesitation in referring it. In any event, it is a true Perognathus, and not 
Cricetodipus at all, as shown beyond question by the obviously naked soles 
and distinctly recognizable lobe of the antitragus. 
PEROGNATHUS MONTICOLA, Baird. 
Mountain Pocket-mouse. 
Perognathus monticola, Barrp, M. N. A. 1857, 422, pl. 51, figs. 3a-h (St. Mary’s, Rocky Mountains).— 
Suckt., P. R. R. Rep. xii, pt. ii, 1860, 101 (notice of the same specimen).—CouEs, Proc. 
Phila. Acad. 1875, 293 (described from another specimen from Fort Crook, Cal.).—? Cours 
& Yarrow, Zoél. Exp]. W. 100 Merid. 1875, 110 (two specimens doubtfully referred here). 
Perognathus mollipilosus, Cours, Proc. Acad. Nat. Sci. Phila. 1875, 296 (provisional appellation). 
? Abromys lordi, GRAY, P. Z.S.1868, 202. (Teste Alston, epist. ) 
Diacnosts (No. 7251, Mus. Smiths. Inst., @, Fort Crook, Cal., J. 
Feilner).—Size of Mus musculus. Tail, including hairs, an inch longer than 
the head and body, the vertebrae alone over half an inch longer. Hind foot 
nearly one-third as long as head and body; naked strip on sole very narrow 
posteriorly; antitragus with a great, flat, rounded, upright lobe, but no lobe 
of tragus opposite, the notch being defined in front by the outer edge of the 
ear itself, Tail not penicillate nor crested; rather thinly but nearly uniformly 
haired throughout. Pelage very soft and smooth for this genus—much as in 
Cricetodipus. Color of upper parts descending on the fore leg to the wrist. 
A fulvous lateral stripe, indistinct but evident; hairs of under parts pure 
white to the roots; tail bicolor. Above, yellowish-cinnamon lined with black- 
ish, the latter predominating; below, white. 
Dimenstons.—Length, 2.50; tail-vertebree, 3.20; hind foot, 0.80. 
Hasirat.—St. Mary’s Mission, west of Rocky Mountains, to Otter Creek, 
Utah, and Fort Crook, California. 
