264 



PROCEEDINGS OF THE ACADEMY OF 



[1894. 



tare of dark tipped hairs and sometimes showing an olivaceous tinge ; 

 under parts and feet white; lateral stripe faint; 

 tail bicolor, white below, dark above, but pale on 

 proximal half. Some specimens have a pale ful- 

 vous band along the side of the tail between the 

 dark upper side and the white under side. 



Cranial characters. — Skull large, and agreeing 

 in the main with other members of the olivaceus 

 group, but differing in the large size of the mastoid 

 bullte, which are much more swollen than in any 

 of the others. The audital bulhe meet or nearly 

 meet anteriorly below the basisphenoid. The in- 

 terparietal is strongly pentagonal and short trans- 

 versely. 



Fig. 2. P. colum- 

 bianiis, ^ . 



Perognathus nevadensis sp. nov. (Fig. 3). 



Type from Halleck, East Humboldt Valley, Nevada. No. 54,828, 

 $ , ad., U. S. Nat. Museum, Department of Agriculture Collec- 

 tion. Collected July 4, 1893, by Vernon Bailey. (Original num- 

 ber 4,070.) 



Measuremenis (taken in flesh). — Type: Total length, 127 mm; 

 tail vertebne, 72; hind foot, 19. Ear from anterior base 7 (in dry 

 skin). Average measurements of 24 specimens from type locality: 

 Total length, 133; tail vertebra, 72-4; hind foot, 18*7. 



General characters. — Size small; tail long; pel- 

 age silky; color grayish. Similar to P. longi- 

 iiieinbi'u but with shorter tail, and color grayish 

 instead of buffy ochraceous. 



Color. — Upper parts buffy gray, everywhere 

 darkened by an abundant admixture of fine black- 

 tipped hairs; a dull buffy-ochraceous lateral stripe 

 which spreads out over the belly, leaving only the 

 throat and pectoral region white; tail indistinctly 

 bicolor, dark above (darkest near tip), buffy 

 ochraceous below. 

 Cranial and dental characters. — Skull small, mastoid bullte large; 

 interparietal pentagonal. Skull siniilar to that of P. longimembris 

 but lower premolar decidedly larger than last molar, and m i larger 

 than m y- 



Fig. ;i I", 

 dcnsii^ 



lirvil- 



