20 NORTH AMERICAN FAUNA. 



Specimens examined. Total number, 54, from the following localities: 



New York : Long Island, 3 ; Montauk Point, 8 ; Raynor Beach, 1 ; Roslyn, 3 ; 

 Sing Sing (not typical), 1. 



New Jersey : Chatham, 1; Englewood, 1; Mount Holly, 2; 'New Jersey', 1; 

 Phillipsburg, 1. 



Pennsylvania : Chester County, 1 ; Culver Lake, 2; Delaware County, 2 ; Mar- 

 pie (Delaware County),!; Schuylkill, 1 ; Tinicum (Delaware County),!; 

 Upper Darby, 1. 



Maryland: Kensington, 1; Laurel, 4; Prince George County, 5; Sandy 

 Spring, 1. 



District of Columbia : Washington, 2. 



Virginia : Accotink, 1 ; Falls Church, 1. 



North Carolina : Raleigh, 7; Weaverville, 1. 



ZAPUS HUDSONIUS CAMPESTRIS subsp. nov. Prairie Jumping Mouse. 



Type from Bear Lodge Mountains, Wyoming, No. 65872, $ ad., U. S. Nat. Museum, 

 Biological Survey Coll. Collected June 12, 1894, by B. H. Dutcher. Original 

 No. 600. 



Geographic distribution. Great Plains from Manitoba southward to 

 Nebraska and westward to Colorado and Wyoming. 



General characters. Similar to Z. hudsonius, but slightly larger and 

 brighter in color; differing also in cranial characters. 



Color. Slimmer pelage: Sides bright ochraceous-buff, similar to 

 brightest specimens of hudsonius from Eastern States, moderately lined 

 with black-tipped hairs; dorsal area distinct, strongly suffused with 

 color of sides; tail yellowish white below, dark grayish above. Fall 

 pelage: Sides dull yellowish instead of ochraceous; dorsal area nearly 

 black, very slightly necked with yellowish-tipped hairs; dorsal surface 

 of tail much darker than in summer; ears darker, conspicuously 

 bordered with whitish. 



Cranial characters. Skull slightly larger than in Z. hudsonius. Skulls 

 from the type locality, compared with those of Z. hudsonius from Tower, 

 Minn., agree in interorbital breadth; brain case about as wide but 

 higher; incisive foramina slightly larger; process on lower border of 

 maxillary portion of zygoma more pronounced; viewed in profile, the 

 cranium is more evenly curved. 



Measurements. Average of 4 adults from type locality : Total length, 

 222; tail vertebrae, 135; hind foot, 30.5. Skull: Average of 4 wlult 

 skulls from type locality : Basilar length, 18.7; zygomatic breadth, 11.4; 

 mastoid breadth, 10.4; interorbital constriction, 4.2; incisor to post- 

 palatal notch, 8.9; foramen magnum to postpalatal notch, 7.9; fronto- 

 palatal depth at middle of molar series, 6.3. 



General remarks. The present well-marked form replaces^, hudsonius 

 over the northern and more elevated portions of the plains west of 

 Minnesota and Iowa to the base of the Eocky Mountains. The char- 

 acters of this form remain remarkably constant throughout its known 

 range. While no good intergrades have been examined, it doubtless 



