1915.] 



THOMOMYS MONTICOLA GROUP. 



121 



It is in aU probability an isolated form but evidently of ancestral 

 connection with douglasi. 



Specimens examined. — Six skins and seven skulls, from type 

 locality. 1 



THOMOMYS NIGER Merriam. 

 Black Pocket Gopher. 

 (PL vm, fig. 7.) 



Thomomys niger Merriam, Proc. Biol. Soc. Washington, XIV. 117, July 19, 1901, 



Type. — Collected at Seaton, near mouth of Umpqua River, 

 Douglas County, Oregon, by J. Ellis McLellan, October 6, 1894. 

 Type specimen in U. S. Nat. Mus., Biological Survey collection. 



Distrihution. — Coast region of west-central Oregon (fig. 5). 



Characters. — About the size of douglasi, to which it shows nearest 

 relationship in its heavy claws and rounded ear; skuU heavier, 

 shorter; rostrum depressed; upper incisors curved inward; color 

 black; mammae in 4 pairs, inguinal 2-2, pectoral 2-2. 



Color. — Upperparts uniform glossy black with purple and green 

 iridescence; underparts duUer and more plumbeous; feet and distal 

 portion of tail white. Young, sooty black. 



Slcull. — Shorter, wider, and heavier than in douglasi, with heavier 

 rostrum; nasals posteriorly sulcate, with the anterior half abruptly 

 widened, and the posterior tips sharply emarginate; interparietal 

 small; buUse fuller and more rounded than in douglasi; pterygoids 

 thick and wide apart. Dentition heavier. 



Measurements. — Type ( c? ad.): Total length, 225; tail vertebrae, 

 81; hind foot, 30. Female topotype: 214, 71, 30. SMll (of type): 

 Basal length, 33.5, nasals, 14; zygomatic breadth, 22.5; mastoid 

 breadth, 18; interorbital breadth, 6; alveolar length of upper molar 

 series, 8. 



Remarlcs. — This is probably a dichromatic species of which as yet 

 only specimens of the black phase have been secured. The cranial 

 characters place it with douglasi in a group of related but not closely 

 connected forms. 



Specimens examined. — Total number, 22, as follows: 

 Oregon: Mapleton.S; Mercer, 7; Scottsburg (2 miles east), 1 (albino); ^ Seaton,6. 



Thomomys monticola Group. 



THOMOMYS MONTICOLA MONTICOLA Allen 

 California Mountain Pocket Gopher. 

 (PI. II, figs. 9, 9'; PI. VIII, fig. 1.) 

 Thomomys monticolus Allen, Bui. Am. Mus. Nat. Hist., V, 48, Apr. 28, 1893. 



Type. — Collected on-Mount Tallac, California, at 7,500 feet altitude, 

 by W. W. Price, August 8, 1892. Type specunenui Am. Mus. Nat. Hist. 



1 Collected June 26, 1897, by J. Alden Loring. Two are haK-grown, the others adults. 



2 Without skull and not certainly identified. 



