GOLDMAN — TWO NEW RODENTS 
233 
Measurements (type). — Total length, 251; tail vertebrae, 76; hind foot, 38. 
An adult male topotype: 256, 80, 39. Two adult female topotypes respectively: 
247-240 ; 79-70; 39-37. Shull (type): Greatest length, 42.8; zygomatic breadth, 
25.9; interorbital breadth, 9.1; length of nasals, 13.5; upper molariform toothrow, 
8 . 2 . 
Remarks. — In the rich russet color of the under side of the tail C. 1. certus 
departs from its nearer geographic neighbors, C. 1. trepidus, C. 1. chrysodeirus 
and C. bernardinus. In this character it agrees closely with C. 1. castanurus, 
but differs widely from the latter form in much paler general coloration, and in 
cranial details, especially the larger audital bullse. Specimens from Arc Dome, 
Reese River (near head). Monitor Mountains, and Toyabe Mountains, Nevada 
are somewh 0 ,t intermediate in characters between C. 1. certus and C. 1. trepidus, 
but may be assigned to the latter form. 
Specimens examined. — Four, all from the type locality. 
Pero dipus microps preblei subsp. nov. 
Preble’s kangaroo rat 
Type from Narrows, Malheur Lake, Harney County, Oregon. No. 79340, 9 
adult, U. S. National Museum (Biological Survey Collection), collected by E. A. 
Preble, July 23, 1896. Original number 1201. 
Distribution. — Plains regions of southeastern Oregon and northwestern 
Nevada. 
General characters. — Closely allied to P. m. microps and P. m. levipes but 
color darker than is typical of either, and cranial characters distinctive. Differ- 
ing from P. m. levipes in slightly smaller size. 
Color (type). — Upperparts near pinkish cinnamon (Ridgway, 1912), finely 
and rather inconspicuously lined with black; underparts, and extent and arrange- 
ment of white and black markings about as usual in the group. 
Skull, — Similar in general to those of P. m. microps and P. m. levipes, but 
decidedly smaller than that of the latter and differing from both as follows: 
Mastoid and audital bullse smaller, the mastoids less inflated along line of contact 
with parietals and supraoccipital resulting in a more flattened condition of this 
portion of cranium; supraoccipital decidedly broader, less depressed above, and 
more widely separating mastoids; maxillary arches very narrow, with angle 
slightly developed as. usual in the species. 
Measurements (type). — Total length, 263; tail vertebrae, 154; hind foot, 41. 
An adult male topotype, 269, 158, 41. Skull: Length (median line), 33.5; masto- 
idal breadth, 22.4; breadth across maxillary arches, 19.2; least width of supra- 
occipital (upper surface near posterior border of interparietal), 2.5; length of 
nasals, 11.6; upper molariform toothrow, 4.2. 
Remarks. — Specimens referred to P. m. levipes from various localities in 
California, Nevada and Utah are darker than the typical form and indicate 
intergradation with the geographic race here described. 
Specimens examined. — Total number, 11 , from localities as follows: 
Oregon: Narrows (type locality), 7; Summer Lake, 1; Tumtum Lake, 2 . 
Nevada: Granite Creek, Humboldt County, 1. 
Biological Survey, Washington, D. C. 
