1919] Grinnell: New Kangaroo Rats 47 



Diagnosis. — A member of the orclii group of five-toed kangaroo 

 rats. Differs from Perodipus colunihianus Merriam as follows : in 

 paler tone of coloration, which involves much reduction of black or 

 dusky on face, ears, and tail, as well as a decidedly more creamy tint 

 of body color; in larger ear; and in larger and more backward- 

 projecting bullae. Differs from its near neighbor, the altogether 

 distinct P. microps Merriam, in the following characteristics : larger 

 ear, smaller foot, shorter tail, much broader, more sharply angled, and 

 more widely spreading maxillary arches, longer nasals, which are also 

 broader posteriorly, broader interparietal, and more incurved incisors. 



Measurements. — ^The average measurements of ten adult and sub- 

 adult specimens, five males and five females, are as follows : to.tal 

 length 233 mm. ; tail vertebrae 125 mm. ; hind foot 38.7 mm. ; ear, from 

 crown, 11.1 mm. ; greatest length of skull 36.9 mm. ; width of skull 

 across bullae 23.3 mm. ; greatest length of nasals 13.7 mm. ; width of 

 rostrum near end 3.5 mm. ; width of maxillary arch at middle 4.3 mm. 



Distribution. — The material at hand consists of fourteen adult 

 or nearly adult specimens, all from the sagebrush flats in the extreme 

 head of Owens Valley, in the vicinity of Benton, Mono County, Cali- 

 fornia. Three places are represented : Pellisier Ranch, 5600 feet alti- 

 tude, five miles north of Benton Station ; Taylor Ranch, 5300 feet, two 

 miles south of Benton Station ; and the old town of Benton, 5639 feet 

 altitude, four miles west of Benton Station. 



Remarks.- — Perodipus levipes Merriam, Perodipus microps, and 

 Perodipus monoensis, although roughly similar to one another in 

 external appearance, are specifically distinct; each has excellent 

 cranial characters distinguishing it from either of the others, and no 

 evidence of intergradation geographically is at hand. P. mtonoensis 

 is apparently most nearly related to P. columhianu^, of the north- 

 western Great Basin. The latter form is represented in the collection 

 of the Museum of Vertebrate Zoology, from within the state of Cali- 

 fornia, by four specimens from Vinton, Plumas County. Perodipus 

 cohmihianus seems not to have been recorded from California pre- 

 viously to this note. 



Transmitted November 26, 1918. 



