SACCOMYID#—PEROGNATHIDINA—P. FASCIATUS. DdO1 
or more; tail less; hind foot about one inch. ail decidedly shorter than 
head and body, not penicillate. Ears large; antitragus distinetly lobed. 
Soles naked to the heels,—at least along a median strip. Above, reddish-yel- 
low, elosely lined with blackish; below, including fore leg all around, white ; 
these two colors separated by a conspicuous stripe of fawn-color or salmon- 
red running the whole length of the body ; tail distinctly bicolor. 
Hasirat.— United States, west of the Mississippi and east of the Rocky 
Mountains, and northern portions of Mexico. (Originally described from the 
mouth of the Yellowstone; redescribed from Chihuahua. Specimens exam- 
ined by me from Nebraska, Kansas, Texas, and Chibuabua.) 7 
I regret that the material before me includes no specimens in the flesh, 
since I am thereby prevented from giving the size and form of the species 
with desirable precision ; fortunately, however, in this instance the characters 
of the species are so strongly marked that lack of elaborate details of form 
will result in no misunderstanding. The coloration, aloae distinctive, can be 
accurately given from several well-prepared skins before me. 
This species, the type of the genus, exhibits very distinctly the two lead- 
‘ing features of external anatomy which distinguish Perognathus proper from 
Cricetodipus ; namely, the lobe of the antitragus and the naked strip of the 
sole extending quite to the heel. It is much the largest species of the genus 
known to inhabit the United States, considerably exceeding P. penicillatus 
(which about equals Hesperomys leucopus in size), and, in fact, some speci- 
mens are little if any smaller than Tamas quadrivittatus. For the reason 
above given, the dimensions cannot be stated with precision; but the length 
from nose to root of tail is obviously more than four inches in all but one of 
the specimens before me; the tail is decidedly shorter than the liead and 
body (in all the other species treated in this paper it ig as long or longer). 
The vertebra of the tail of the only specimen before me in which these 
bones remain in situ measure less than 4.00 inches, the length of the head 
and body of the same specimen being about 4.50. Likewise, the hind feet 
are proportionally shorter than in any of the other species; they average only 
one inch in length, thus not exceeding those of P. penicillatus, which is a 
smaller animal. On the contrary, the ears are larger, both absolutely and 
relatively, than those of any. other species, standing about 0.40 high, meas- 
ured from the notch; the ears thus project conspicuously above the fur of 
the parts; the flap is suborbicular in outline; the antitragus develops a yery 
