132 



1857. Jaculus hudsonius, Baird, M N. A., 1857, 430, pi. 21, f. 5 a-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. 8.^- 

 Cooper and Suckiey, Nat. Hist. Wash. Terr., 1860, 83, 101, 127.— 

 Hayden, Trans. Amer. Philos. Soc, xii, 1862, 147 (Fort Union).— 

 Samuels, Ninth Ann. Rep. Ma=!S. Board. Agric, 1862, 178 (hab- 

 its. — Gilpin, Proc. and Trans. Nova Scotia Inst , ii, 1870, 60 

 (Nova Scotia).— Allen, Bull. Mus. Comp. Zool., i, 1870, 226 (Mas- 

 sachusetts.— Tenney, Am. Nat., vi, 1872, 380, f. 101 (habits).— 

 Merriam, Ann Rep. U. S. Geol. Surv. Terr, for 1871, 1872, 6&5.— 

 Ames, Bull. Minn. Acad,, i, 1874,- 70 (Minnesota).— Allen, Bull. 

 Ess. Inst., vi, 1874, 60, 65 (Wyoming and Utah). 



1875. Zapus hvdsonius, Coues, Bull. U. S. Geol. and Geog. Surv. Terr., 2d 

 ser., No. 6, 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 Distribution. — 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 I>r. Coues. The 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 

 di.=persion is probably not less than that of Hesperomys leucopus, particur 

 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 

 legs 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 

 rite 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 

 Heiperomys 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 

 bjck aad forth. The nose-pad has two median, vertical grooves; the 



