1911] Swarth: Tiro New Species of Marmots. 203 



Marmota ochracea, new species. 



Yukon ]\Iarmot. 



Type.— Female adult ; no. 5872, Univ. Calif. Mus. Vert. Zool. ; 

 Forty-mile Creek, Alaska, August 19, 1901; collected by C. L. 

 Hall ; orig. no. 477. 



Diagnostic Characters. — Like M. flaviventer, from which it 

 differs in coloration and pattern of markings. 



Coloration. — Hairs of upper parts pale cinnamon-rufous 

 basally, with a black central band. On the forepart of the body, 

 from the neck to a point behind the shoulders, the hairs are the 

 same color at the tip as at the base. From the middle of the 

 body to the rump the exposed portions of the hairs are hoary 

 whitish, producing a distinctly paler effect posteriorly. Tail 

 uniform cinnamon-rufous above and below, slightly darker at the 

 tip. Whole top of head from tip of nose to and including the 

 ears, prout brown. Sides of head and neck, including the eye- 

 lids, the same color as the shoulders and sharply defined against 

 the darker brown of the top of the head. Lower surface of the 

 body and legs all around, hazel. Feet and claws black. 



Skull. — Represented only by a fragment of the rostrum with 

 incisors attached, and the lower jaw : Compared with skulls of 

 M. fiavivoiter these parts are small and weak, the teeth conspic- 

 uously so. 



Remarks. — Only two examples of the new species are at hand, 

 an adult female and a young male, both from the head of Forty- 

 mile Creek, a tributary of the Yukon crossing the Canadian 

 boundary. The latter was mounted but has been removed from 

 its stand. Both were prepared with the anterior portions of the 

 skull left within the skin. Those of the adult have since been 

 removed. 



These two specimens differ from available skins of M. flavi- 

 venter from California and Colorado in various details of colora- 

 tion and markings. They are more yellowish above and darker 

 below, and lack the distinctive head markings of that species. In 

 examples of flaviventer in comparable pelage the head and muzzle 

 are much darker, sometimes black, with a conspicuous white 



