VOL. XI, PP. 103-104 APRIL 26, 1897 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



THREE NEW JUMPING MICE (ZAPUS) FROM THE 

 NORTHWEST. 



BY C. HART MERRIAM. 



There seem to be two well marked groups of species among 

 the American Jerboas or Jumping Mice the small Zapus hud- 

 sonius and its immediate allies from the region east of the Rocky 

 Mountains, but including the new form here described under 

 the name tenellus, and the large princeps and trinolatus and their 

 allies from the mountains of the west and the northwest coast. 

 Three new forms are here described one from Kamloops, in the 

 interior of British Columbia, and two from southwestern Oregon. 

 Of the latter, one inhabits the Cascade Range about Crater Lake, 

 the other the Rogue'River Valley. 



Zapus tenellus sp. nov. 



Type from Kamloops, British Columbia. No. 66932, $ ad., U. S. Nat. 

 Mus., Biological Survey Coll. Collected August 25, 1894, by Clark P. 

 Streator. Original No. 4196. 



General characters. Size small ; ears rather large ; coloration dark ; hind 

 feet very slender. Similar to Z. hudsonius, but less yellow and very much 

 darker and tail longer. 



Color. Dorsal area not sharply defined, grizzled with yellowish; sides 

 olive-yellowish, heavily lined with black hairs ; nose, ears, and inner side 

 of legs to heel dusky; tail sharply bicolor : dusky above and at tip all 

 round, whitish below ; fore and hind feet soiled whitish. 



Cranial characters. Skull similar in size and characters to Z. hudsonius. 



Measurements. Type specimen : total length, 216 ; tail vertebrae, 134 ; 

 hind foot, 31. Average of four specimens from type locality : total length, 

 208; tail vertebrge, 128.5; hind foot, 31. 



23 Bior,. Soc. WASH., Vol.. XI, 1897 (103) 



