132 
1857. Jaculus hudsonius, Baird, M N. A., 1857, 430, pl. 21, f. 5a-e.—Newb., 
P. R. R. Rep., vi, 1857, 59 (California) —Baird, P. R. R. Rep., 
x, 1859, Gunnison’s and Beckwith’s Routes, Mamm., p. 3.— 
Cooper and Suckley, Nat. Hist. Wash. Terr., 1860, 83, 101, 127.— 
Hayden, Trans. Amer. Philos. Soc., xii, 1862, 147 (Fort Union).— 
Samuels, Ninth Ann. Rep. Mass. Board. Agric., 1862, 178 (hab- 
its.—Gilpin, Proc. and Trans. Nova Scotia Inst, ii, 1870, 60 
(Nova Scotia).—Allen, Bull. Mus. Comp. Zodl., i, 1870, 226 (Mas- 
sachusetts.—Tenney, Am. Nat., vi, 1872, 330, f. 101 (habits).— 
Merriam, Ann Rep. U.S. Geol. Surv. Terr. for 1871, 1872, 665.— 
Ames, Bull. Minn. Acad., i, 1874, 70 (Minnesota).—Allen, Bull. 
Kss. Inst., vi, 1874, 60, 65 (Wyoming and Utah). 
1875. Zapus hudsonius, Coues, Bull. U. 8. Geol. and Geog. Surv. Terr., 2d 
er., No. 5, 1875, 254; Mon. N. A. Rodentia, 1877, 467.—Coues 
and Yarrow, Zool. Expl. W. 100th Merid., 1875, 99.—Jordan, 
Man. Vert., 1878, 2d ed. ; 
Geographical Distribultion.—This species inhabits the greater part of 
British America and the United States. Its exact northern and south- 
ern limits are not yet determined. Specimens are reported from Great 
Slave Lake, latitude 62, by Dr. Coues. Tie same author has observed it 
personally in Virginia. Mr. Langdon has “recognized it satisfactorily ” 
in Ohio, where, indeed, we should naturally expect an animal whose 
dispersion is probably not less than that of Hesperomys leucopus, particu- 
larly as it shows a strong preference for woodlands, and as there are no 
very extensive treeless areas in Ohio. 
Description —This animal has a general murine form, modified by the 
extreme development of the hind limbs, particularly of the feet; the 
leos and thighs are large and muscular ; the body tapers from the fore-legs, 
and is large posteriorly, in correlation with the greatly developed hind- 
legs. This kangaroo-like structure enables this little animal to take 
enormous leaps, of even eight to ten feet when alarmed, and has-given 
rise to the common names, ‘“ Kangaroo-mouse,” Jumping-mouse.” The 
tail, in relative length, exceeds that of any other of our rodents; it is 
always longer than the head and body, sometimes nearly twice as long. 
This feature has suggested the vernacular prefix: “‘ Long-tailed,’ by which 
it is distinguished from the “‘ Wood-mouse,” and other names common to 
Hesperomys leucopus. The head is conoidal, with a prominent and some- 
what blunt snout, and retreating. under jaw. The muzzle is small and 
naked, inferior in position; over it the skin crosses with a deep, trans- 
verse fissure, | making an, imperfect, overhanging flap, freely moveable 
bick and forth. The nose- -pad has two median, vertical grooves; the 
