aACCOMYII)^:— rRKOONATIIIDINili:— p. r'ASCIATUH. 



501 



or more; tailless; hind loot nboiit ono incili. 'J'nil dccidodly shorter than 

 head and hody, not penicillutc!. Kars Jiirffc; antitra/^im distinctly loljod. 

 Soles nuked to the heels, — at leiist lUoojj; a median strip. Above, niddish-yel- 

 low, elosely lined with blackish; below, includiug fore leg nil urouiid, while; 

 tli. e two colors separated by u conspicuous stripe of tiiwn-color or salmon- 

 red running the whole length of the body ; tail distinctly bicolor. 



Haihtat. — United States, west of the Mississippi and east of the R(K'ky 

 Mountains, and northern portions of Mexico. (Originally described from the 

 mouth «»f the Yellowstone; redescribed from Chihuahua. Specimens exam- 

 ined by me from Nebraska, Kansas, Texas, and Chihuahua.) 



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 8|)ecic8 

 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, alone distinctive, can be 

 accurately given from several well-prepared skins before me. 



This speciesi 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 nntitrugus and the nuked 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. penicMitus 

 (which about equals Hesperomijii leucopus in size), and, in fact, some speci- 

 mens are little if any smaller than lamias quadrkntlatm. 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 head and 

 body (in all the other species treated in this paper it is as long or longer). 

 The vertebne 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. jienicillalus, 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 very 



