52 



NORTH AMEEICAN FAUNA. 



[no. 39. 



Distribution. — Inner ridge of the Coast Ranges along west side of 

 the San Joaquin Valley, Cal. (fig. 6) . 



Characters. — Size small, about as in navus; color bright yellowish 

 brown, much as in angularis, brighter than summer pelage of lottse; 

 skull a miniature of the hottx skull, with short, wide braincase and 

 projecting incisors. 



Color. — Summer pelage (March and October specimens) : Upper- 

 parts bright sayal brown, with but slight darkening of black-tipped 

 hairs; ears and ear patches black; nose dusky; underparts clear, 

 bright ochraceous-tawny; lips and lining of cheek pouches white; 

 tail buffy; feet whitish. Winter pelage (as shown in a few not fully 

 typical October specimens from Pacheco Pass and Pacheco Peak) : 

 Much darker than in summer, but apparently not so black as in 

 hottse. 



Slcull. — Similar to that of hottse but smaller and slenderer, with 

 especially slender rostrum and zygomatic arches. Dentition: Teeth 

 very light, incisors slender and projecting well beyond tip of nasals, 

 pale yellow or whitish. 



Measurements. — Type (9 young ad.): Total length, 180; tail 

 vertebrae, 60; hind foot, 25. Female topotype: 193, 65, 26.^ Aver- 

 age adult male from Pacheco: 218, 65, 30; female: 201, 57, 28. Slcull 

 (of type, 9 ad.): Basal length, 31; nasals, 10.3; zygomatic breadth, 

 22; mastoid breadth, 17.9; interorbital breadth, 7; alveolar length 

 of upper molar series, 7.2. Skull of topotype ad.): 34, 12, 24, 

 19.3, 6, 7.2. Skull of old male from Pacheco Pass:^ 37, 12, 25, 20.7, 

 5.5, 7.5. SkuU of old female: 32, 10, 22, 19, 5.5, 7. 



RemarJcs. — This depauperate form of hottse se^is to be a product 

 of the hot and arid Upper Sonoran inner ridge of the Coast Ranges 

 along the west side of the San Joaquin Valley, in what Dr. Grinnell 

 calls the hillside juniper association." It needs no comparison 

 with the robust and massive-skulled angularis of the vaUey along its 

 eastern border, but could easily be confused with intermediates 

 between leucodon and navus from similar arid ridges north of San 

 Francisco Bay. The skull, however, is more nearly of the true hottse 

 type. 



Specimens examined. — Total number, 19, as follows: 

 California: McKittrick, divide west of (Kern County, 3,000 feet altitude), 1; 

 Pacheco Pass (Santa Clara County), 6; Pacheco Peak (Santa Clara County), 

 6; Sweeney's Ranch (Diablo Range, Merced County), 6. 



1 Foot measured dry. 



- No. 150799, Biological Survey collection. 



