Merriam N~ew Species of Thomomys. 117 



Thomomys niger sp. nov. 



Type from Seaton, near mouth of Umpqua River, Oregon. No. 69,407, 

 $ ad., U. S. National Museum, Biological Survey Collection. October 

 0,1894. ,J. K. McLellan. Original No. 1147. 



Characters. Size medium: feet large; tail medium; ears short; head 

 and body all round gloss tj dale black with greenish iridescence; nose duller, 

 feet and tail white, sometimes irregularly blotched with dusky. 



Cranial characters. Skull of medium size, massive, showing well de 

 veloped temporal ridges; interparietal oval or broadly subtriangular; zy 

 gomata moderately spreading and rounded; nasals emarginate, strongly 

 and abruptly narrowed on posterior two-thirds. 



Remarks. In coloration the 6 specimens at hand from the type locality 

 strikingly resemble T. orizabtc from southern Mexico. They differ from 

 orizabtc in having less black on the feet and tail, and in marked cranial 

 characters. The nearest relative of T. niger appears to be T. douglasi 

 from the Columbia River. It differs from douglasi, apart from color, in 

 slightly smaller size and in the following cranial characters: frontals 

 narrower interorbitally; zygomata rounded instead of angular, their 

 outer sides parallel instead of diverging anteriorly; nasals abruptly con 

 stricted between anterior and middle thirds and narrower posteriorly 

 (instead of having straight sides); bulla? heavier anteriorly; molar series 

 of same length as in douglasi but broader; incisors strikingly large and 

 broad; under jaw deep, the angular process much more heavily devel 

 oped. 



Measurements. T\"pe specimen ( $ ad.): total length 225; tail vertebra 1 

 81; hind foot 30. Average of 5 adults from type locality: total length 

 215: tail vertebra? 72; hind foot 30. 



