^922] Kellogg: Synopsis of Microtus Mordax 289 



Canon (7300 feet), 3; 1 mile east Merced Lake (7500 feet), 5; Vogel- 

 sang Lake (10,300 feet), 7; Fletcher Creek near Vogelsang Lake 

 (10,100 feet), 4. inyo county: Can-oil Creek (5500 feet), 1; Little 

 Onion Valley, Sierra Nevada Mountains (7500 feet), 28 ; Onion Valley, 

 Sierra Nevada Mountains (8500 feet), 45; Kearsarge Pass (10,500 

 feet), 25 ; Roberts Ranch, Wyman Creek, White Mountains (8250 feet), 

 6; Silver Caiion, seven miles east of Laws (7000 feet), 20; Little 

 Cottonwood Creek, Sierra Nevada Mountains (9500 feet), 5. fresno 

 COUNTY: Hume (5300 feet), 8 ; Bullfrog Lake (10,600 feet), 13 ; Bubbs 

 Creek (9500 feet), 4; King's River Canon (5000 feet), 29; Horse 

 Corral Meadow (7600 feet), 10. tulare county: Tavlor Meadow 

 (7000 feet), 8; two miles east Kern Peak (9300 feet), 1; Jordan Hot 

 Springs (6700 feet), 7; Cannell Meadow (7500 feet), 24; Siretta 

 Meadows (9000 feet), 13; Jackass Meadow (7750 feet), 17; Monache 

 Meadow (8000 feet), 12; Whitney Meadow (9800 feet), 18; Little 

 Brush Meadow, Olancha Peak (9750 feet), 9; Twin Lakes, Sequoia 

 National Park (10,238 feet), 6; Sherman Creek, Sequoia National 

 Park, 1. 



Diagnosis. — Size medium (hind foot, 20 to 22 mm.; condylobasal 

 length of skull in largest individuals, 29.5 mm.) ; second upper molar 

 without postero-internal triangle ; first lower molar with four reentrant 

 angles on outer side ; skull long, of moderate width, angular and much 

 ridged in old adults (ratio of zygomatic breadth to condylobasal 

 length about 55 per cent), the intertemporal region rarely developing 

 a ridge with age ; auditory bullae large and inflated ; pelage darker 

 than in mordax, more brownish; ears moderate in size (10 to 14 mm.). 



Measurements. — Average of 51 specimens : total length, 195.97 

 mm. (190-221) ; tail vertebrae, 68.39 mm. (55-77) ; hind foot, 22.2 

 mm. (21-24) ; condylobasal length of skull, 28.21 mm. (26.8-29.5) ; 

 occipito-nasal length, 27.68 mm. (25.6-29.9) ; basilar length, Hensel, 

 25.0 mm. (24.1-26.3) ; nasal length, 8.4 mm. (7.3-9) ; zygomatic width, 

 15.8 mm. (14.8-16.9); interorbital constriction, 4.05 mm. (3.7-4.5); 

 interparietal width, 8.7 mm. (7.9-9.6) ; shelf of bony palate, 14.15 mm. 

 (13.5-14.8) ; height cranium at bullae, 10.01 mm. (9.5-10.8) ; mastoid 

 width, 12.77 mm. (11.9-13.3) ; length upper molar series, 6.78 mm. 

 (6.1-7.4) ; length mandible, 16.94 mm. (15.6-18.3). 



Color. — Upperparts and sides as a rule darker than mordax. Mass 

 effect of dorsal area more strongly mixed with brownish and blackish 

 overhairs. Dorsal stripe less sharply contrasted with coloration of 

 sides. In fresh pelage : hairs of upperparts blackish slate basally, with 

 light tipped portions normally clay color, but may vary from cinna- 

 mon buff to tawny olive ; the long overhairs grading from bone brown 

 to aniline black. Sides lighter than upperparts, more grayish, with 

 long overhairs not materially darkening the ground color ; rump 

 grayer than rest of upperparts. The plumbeous hair bases are usually 

 visible in pelage of sides and rump, and affect general coloration. 

 Underparts pale gray, with blackish slate hair bases showing through 

 at surface to a varjdng degree in different individuals ; anal area pure 

 white. Whiskers mixed with white and aniline black. Upper and 

 lower lips whitish. Cheeks grayish with slight infusion of cinnamon 



