156 University of California Publications in Zoology [Vol. 10 



Material : The basis for this description is as follows : Forty- 

 nine specimens of Perognathus longimembris longimenibris : 

 Corral Hollow, eight miles southwest of Tracy, San Joaquin 

 County, 5; Sweeney's Ranch, 22 miles south of Los Bafios. Mer- 

 ced County, 3; Lane Bridge, ten miles north of Fresno, Fresno 

 County. 2; Raymond, Madera County, altitude 940 feet, 3; 

 Jesbel, 540 feet, eight miles west of Raymond. Madera County. 

 1 ; Tipton, altitude 266 feet. Tulare County. 6 ; Earlimart, or 

 Alila, altitude 280 feet, Tulare County, 5 ; eight miles north- 

 east of Bakersfield, 21; Tejon Canon. 1; Rose Station, 1; San 

 Emigdio, 1 ; the last four stations in Kern County, and the 

 last three specimens from the Biological Survey collection, U. S. 

 National Museum. Forty-one of Perognathus longimembris neg- 

 h clus: McKittrick, Kern County, 37; Carrizo Plain, seven 

 miles southeast of Simmler, San Luis Obispo County, 3; San- 

 tiago Spring, Carrizo Plain, San Luis Obispo County, 1. 



Descriptive Remarks: Coloration. — All the specimens con- 

 sidered were collected between March 16 and May 28, so pre- 

 sumably all the adults exhibit the same pelage, the more or less 

 worn winter coat. The new form, Perognathus longimembris 

 in gh rhis. is very much lighter than /'. /. longimembris. The 

 ground coloration is apparently the same in both, and comes 

 nearest the ochraceous-buff of Ridgway's Nomenclature of 

 Culms ilSSUi. The dissimilarity in appearance, as already 

 noted, is the result of a difference in extent of black tipping on 

 the hairs. P. 1. neglectus is practically pure ochraceous-buff in 

 coloration, there being merely a sufJSfestion of black. On the 

 other hand, /'. /. longimt minis is much darkened, the pure ochra- 

 ceous-buff being discernible only along the lateral line, in a 

 spot behind each ear, and on outer sides of fore and hind limbs. 

 Ears in neglectus not so dusky on inner surface. Tail lighter 

 colored than in longimi rribris. 



Fore and hind feet and underparts pure white. Two speci- 

 mens of longimembris from Earlimart (nos. 14501, 14503) are 

 unlike the rest of the series, in that they lack the dorsal darken- 

 ing. The tone of their coloration approaches ochraceous instead 

 of ochraceous-buff, however, so making them distinct from neg- 

 lectus. They are smaller, too, than the specimens of the latter. 



