1915.] 



THOMOMYS BOTM GROUP. 



45 



Specimens examined. — Total number, 93^ as follows: 

 Nevada: Argenta, 1; Austin, 9; Battle Mountain, 15; Big Creek, 3; Halleck, 5; 



Independence Valley, 1; Lovelocks, 10; McDermitt, 2; Paradise, 8; Quinn 



River Crossing, 14; Winnemucca, 7. 

 Oregon: Alvord, 1; Alvord Lake, 10; Tumtum Lake, 7. 



Thomomys bottse Group. 



THOMOMYS BOTT^ BOTT^ (Eydoux & Gervais). 



California Pocket Gopher. 



(PI. n, fig. 3; PI. Ill, fig. 4; text fig. 2.) 



Oryctomys (Saccophorus) bottse Eydoux & Gervais, Mag. de Zool., VI, 23-24, pi. 21, 

 fig. 4, 1836. 



Thomomys bottse Baird, Proc. Acad. Nat. Sci. Philadelphia, VII, 335, 1855, 

 Thomomys bulbivorus Baird, Mamm, N. Am., 389, 1857. Not Diplostoma bulbivorum 

 Richardson. 



Type. — Collected on coast of California/' probably at Monterey 

 or San Francisco. Type in '^Collection de la Faculte des Sciences/' 

 Paris. 



Distribution. — Coast region of California, from Sonoma County 

 (Freestone) south to San Diego (fig. 6). 



Characters. — Size large, males much larger than females; average of 

 hind foot in males, 33 mm., in females, 28 mm; ears short, a mere 

 thickened rim; color dull, dark yellowish brown, nearly unicolor; 

 skull well arched, heavily ridged, and angular, with slightly project- 

 ing incisors; grooves on inner edge of incisors very small; mammae in 

 4 pairs, inguinal 2-2, pectoral 2-2. 



Color — Winter pelage: Upperparts dark ochraceous, heavily clouded 

 with black-tipped hairs; underparts lightly washed with dull ochra- 

 ceous over the plumbeous underfur, often ahnost as dark as upper- 

 parts; ear patch, nose, and cheeks blackish; lips and fining of pockets 

 white; tail usuafiy dusky or brownish gray ; feet usuafiy white. Sum- 

 mer pelage: Very similar, but sfightly brighter, clearer ochraceous. 



SJcull. — Adult male : Heavy and angular with long, decurved ros- 

 trum; lateral ridges occasionally meeting in very old age in sagittal 

 crest; nasals long, cuneate or slightly spatulate, narrow, and gener- 

 ally emarginate posteriorly; auditory meatus large and sfightly 

 inflated; buUse rather depressed and angular; upper incisors project- 

 ing sfightly beyond -tip of nasals. Adult female: Much smafier, 

 slenderer, and less ridged than in males, but with the same arched 

 outline, slender rostrum, and projecting incisors. 



Measuixments.-— Aver Sige of 5 adult males from near Monterey : Total 

 length, 267; tail vertebrse, 81; hind foot, 33. Average of 5 females: 

 219, 69, 28. Slcull ( ad.):' Basal length, 45; nasals, 16.5; zygo- 



iNo. 107856, U. S. Nat. Mus., from near Monterey, Cal. 



