DESCRIPTION OF A NEW SPECIES OF MOUSE, PHENACOMYS 

 LONGICAUDUS, FROM OREGON. 



BY 



Frederick W. True. 



Curat07- of the Department of Mammals. 



The Smithsonian Institution has recently received from one of its 

 valued correspondents, Mr. Aurelius Todd, of Eugene City, Oregon, a 

 dry skin of an interesting and apparently undescribed species of mouse. 

 It belongs to the genus Phenaco7nys, recently established by Dr. C. H. 

 Merriam, but, unlike the species described by that author, resembles 

 the field-mice of the genus Eesperomys^ rather than the ArvicoUnw, or 

 meadow-mice. This arises chiefly from its possessing a long tail like the 

 field-mice, and I have therefore chosen for the species the name of 

 Phenacomys longicaiuhis. 



Phenacomys longicaudus sp. uov. 



Size moderate, about equaling that of Uesperomys leucopus. Ears 

 moderate, nearly concealed by the surrounding fur. Hind foot not 

 relatively longer than in the other species of the genus. Tail long; 

 with the hairs, equal to the body in length. 



Color above nearly uniform bright rusty brown ; only the tips of the 

 hairs are of this color, the remainder being dark plumbeous. Mixed 

 with the brown-tipped hairs are numerous longer black hairs. Under 

 surfaces white, slightly tinged with rusty brown, especially on the 

 abdomen. The hairs of the throat are white to the base, but elsewhere 

 they are only tipped with light color, the lower portions being plum- 

 beous. 



The tail is dusky chocolate-brown above and below. Fore feet brown, 

 like the upper surface of the body ; toes more or less dusky. Hind 

 feet similar, but the toes more dusky. A spot on the outside of the 

 metatarsus lighter than the rest of the foot. A portion of the whiskers 

 dusky, the rest whitish. Xose dusky. 



Measurements. (Dry skin No. Hyti? type). — Total length, 148'""'; tail, 

 with hairs, 62"""; hind foot, 20.2"'"'; ear from behind, 4.6'""'.* 



The skull belonging to the type is badly broken, and it is only pos- 

 sible to give the dimensions of some of its parts. 



* These measurements, having been taken from the dry skin, are of course only 

 approximately correct. 



Proceedings National Museum, Vol. XIII— No. 826. 



303 



