SACCOMYID.E— PEUOGNATHlDlNvE— P. MONT1COLA. 509 



which embraces Arizona and the contiguous part of California on t lie 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 

 parvus" of LeConte, /. c. 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. 



rerognathus monticola, Baird, M. N. A. 1857, 422, pi. 51,- figs. 3a-h (St. Mary's, Rocky Mountains). — 

 Suckl., P. R. R. Rep. xii, pt. ii, I860, 101 (notice of tbe same specimen). — Coues, Proc. 

 Phila. Acad. 1875, 293 (described from another specimen from Fort Crook, Cab). — ? Coues 

 & Yarrow, Zool. Expl. W. 100 Merid. 1875, 110 (two specimens doubtfully referred here). 



Pcrognathus mollipilosus, Coues, Proc. Acad. Nat. Sci. Phila. 1875, 296 (provisional appellation). 



? Abromijs lordi, Gray, P. Z. S. 1868, 202. ( Teste Alston, epist. ) 



Diagnosis (No. 7251, Mus. Smiths. Inst., 9, Fort Crook, Cal., J. 

 Feilner). — Size of Mus musculus. Tail, including hairs, an inch longer than 

 the head and body, the vertebra 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. 



Dimensions. — Length, 2 50; tail-vertebras, 3.20; hind foot, 0.80. 



Habitat. — St. Mary's Mission, west of Rocky Mountains, to Otter Creek, 

 Utah, and Fort Crook, California. 



