_Zapus hudsonius_ 420 _Zapus hudsonius acadicus_ (Dawson) 432 _Zapus hudsonius alascensis_ Merriam 435 _Zapus hudsonius americanus_ (Barton) 436 _Zapus hudsonius campestris_ Preble 441 _Zapus hudsonius canadensis_ (Davies) 442 _Zapus hudsonius hudsonius_ (Zimmerman) 443 _Zapus hudsonius intermedius_ Krutzsch 447 _Zapus hudsonius ladas_ Bangs 449 _Zapus hudsonius pallidus_ Cockrum and Baker 450 _Zapus hudsonius preblei_ Krutzsch 452 _Zapus hudsonius tenellus_ Merriam 453 Genus =Zapus= Coues _Genotype._--_Dipus hudsonius_ Zimmerman. EXTERNAL CHARACTERS.--Muriform in general appearance; forelimbs small, short; hind limbs greatly developed; hind feet long and narrow; tail tapering, attenuate, subcylindrical; head long and mouse-shaped; eyes small and situated midway between nose and ear; external ear somewhat longer than surrounding hair and provided with antitragal flap which can cover external auditory meatus, and in company with tragus completely close opening; upper lip without median groove; internal cheek-pouches well developed and opening at corners of mouth; mystacial vibrissae conspicuous; supercilliary vibrissae few; genal tuft absent; teats normally eight and arranged in pairs (one pectoral, two abdominal, and one inguinal); anterior and posterior pairs frequently undeveloped; general pelage coarse; color of pelage varies somewhat in different species but always follows single basic pattern of broad dorsal band of some shade of brown or brownish-yellow darkened with brownish-black, sides of a lighter tone and slightly streaked with brownish-black, underparts snow-white, sometimes suffused with color of the sides and usually separated from color of sides by sharp line of clear brownish-yellow; backs of forefeet and hind feet grayish-white; tail distinctly bicolor, dark brown above and yellowish-white below; ears dark and narrowly edged with light color. [Illustration: FIG. 44. Map showing distribution of the genus _Zapus_.]