412 PROCEEDINGS OF THE ACADEMY OF [1893. 



A male and female from White Water on the western side of 

 Mohave Desert represent the species. They are alike in all impor- 

 tant respects. 



(i. Perognathus alticolus, sp. nov. (Type Xo. 1615. $ , Col. Acad. Nat. Sciences, 

 Phila.; San Bernardino Mts., California. Sept. 22, 1893, col. by R. B. Herron). 



Description. — Most similar to P. apache and P. inornatus, differ- 

 ing crauially, and in larger size from either, less yellow than apache 

 and more decidedly lined with black than inornatus. Size small, 

 tail equals length of head and body, or longer, slightly crested 

 penicillate. Above yellowish brown heavily but finely lined with 

 blackish. Pelage very soft and full. Bases of hairs above plumb- 

 eous for three-fourths their length. A tawny lateral stripe from 

 nose to and including upper half of tail. Distal third of tail above 

 becoming blackish. One- fourth of heel end of soles, haired. Lower 

 parts, feet, fore legs and lower edge of ear white to roots of pelage. 



Measurements (from dry skin). — Total length, 157; tail vertebrae, 

 77; pencil, 9; hind foot, 20; ear from crown, 5. Skull — Basilar 

 length, 16; mastoid breadth, 12-5: interorbital constriction, 6; 

 length of nasals, 8*6; length of mandible, 10*5; height of coronoid 

 process, 4*6. 



Cranially alticohis may be distinguished from both its allies by the 

 well defined separation of audital bullae below. Its lower premolar 

 is similar to that of inornatus, but the mastoids of the latter are very 

 much larger than those of alticolus. The same maybe said of apache. 

 P. alticolus belongs to the fasciatus group of the subgenus Perogna- 

 thus. 



Skull figures of this species and the two Dipodomys above described 

 will probably appear in the final report of Mr. Herron' s collections. 



