CHECK-LIST OF THE SPECIES AND SUBSPECIES OF THE GENUS ZAPUS

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Zapus trinotatus[385]
Zapus trinotatus eureka A. B. Howell[389]
Zapus trinotatus montanus Merriam[390]
Zapus trinotatus orarius Preble[391]
Zapus trinotatus trinotatus Rhoads[392]
Zapus princeps[394]
Zapus princeps cinereus Hall[399]
Zapus princeps curtatus Hall[400]
Zapus princeps idahoensis Davis[401]
Zapus princeps kootenayensis Anderson[404]
Zapus princeps luteus Miller[406]
Zapus princeps minor Preble[407]
Zapus princeps oregonus Preble[409]
Zapus princeps pacificus Merriam[412]
Zapus princeps princeps Allen[414]
Zapus princeps saltator Allen[416]
Zapus princeps utahensis Hall[418]
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.

Fig. 44. Map showing distribution of the genus Zapus.

Cranial characters.—Skull short in relation to width, deep relative to other dimensions, somewhat convex; delicate, papery, without strong angularity; braincase relatively unexpanded; antorbital foramen obliquely oval and transmits masseter muscle of great size; foramen in inferior ramus of zygomatic process of maxillary for passage of superior maxillary branch of trigeminal nerve small; zygomata not wide-spreading; underside of zygoma nearly horizontal, upper edge anteriorly rises prominently owing to extension of jugal upward along maxillary; jugal and lachrymal in contact; one ramus of zygomatic process of maxilla arises directly above other; rostrum thick basally and relatively attenuate distally; ends of nasals project noticeably beyond incisors; premaxillaries develop strong alveolar plate separating superior incisors for half their length; palatal bones shortened posteriorly, free edge often concave; incisive foramina long, broad, and separated by bulbose (except at posterior end) bony septum; mastoid bullae absent; auditory bullae short and transversely placed; postorbital process never present; parietals nearly square, sometimes emarginate in front; angle of mandible flattened and bent inward; coronoid process weak, acute, and slopes strongly upward.