1894.] NATURAL SCIENCES OF PHILADELPHIA. 267 



Perognathus (Chaetodipus ) strphensi sp. iiov. (Fig. 7). 



Type from N. W. Arm of Death Valley (Mesquite Valley), 

 California. No. §^3, S , ad., U. S. Nat. Museum, Department of 

 Agriculture Collection. Collected April 6, 1891, by Frank 

 Stephens. (Original number 258.) 



Measurements (taken in flesh). — Type: Total length, 177 mm; tail 

 vertebne, 96; hind foot, 21. Ear from anterior base, 7'5 (in dry 

 skin). Average measurements of 2 specimens from type locality : 

 Total length, 177; tail vertebra, 95; hind foot, 21. 



General characters.— S\ze small; tail vertebrjB slightly longer than 

 head and body; tail scantily crested; ears medium; tragus higher 

 than broad ; pelage rather soft ; no spines on rump or elsewhere. 

 This species is evidently a dwarf of the penicillatus 

 group, though the area it inhabits is completely 

 isolated from the range of the penicillatus type. 



Color. — Upper parts butty-drab varying to pale 

 drab-brown; a rather large pale ring around eye; 

 under parts, feet, and fore legs white; no lateral 

 line; tail bicolor, slightly darker than back above 

 and terminally, white beneath. 



Cranial characters. — Skull similar to that of in- 

 Fig. 7. P. ste- termedius, but much smaller and flatter, with inter- 

 pheiisi. parietal broadly and flatly pentagonal instead of 



strap shaped, and audital bullte more slender. In size and general 

 form the skull agrees most closely with arenarius from the middle 

 region of the Peninsula of Lower California. It ditters from aren- 

 arius in having the rostrum and nasals much broader and the 

 audital bulla? much less swollen. 

 Perognathus (Chaetodipus) intermedius canescens subsp. nov. 



Type from Jaral, Coahuila, Mexico. No. 51,016, S , yg. ad., 

 U. S. Nat. Museum, Department of Agriculture Collection. Col- 

 lected January 14, 1893, by Clark P. Streator. (Original num- 

 ber 2,557.) 



Measurements (taken in flesh). — Ti/pe : Total length, 1 93 mm ; tail 

 vertebra, 117 ; hind foot, 22. Ear from anterior base, 8 (in dry 

 skin). Average measurements of 2 specimens from type locality : 

 Total length, 189; tail vertebme, 111; hind foot, 22. 



General characters. — Similar to interinedins, but slightly larger and 

 much grayer. 



